diff --git a/src/Container/Container.php b/src/Container/Container.php
index a6c2143..a62698a 100644
--- a/src/Container/Container.php
+++ b/src/Container/Container.php
@@ -10,7 +10,7 @@ interface Container
 {
     public function register(string $className, callable $definition): self;
 
-    public function singleton(string $className, object|callable $definition): self;
+    public function singleton(string $className, object|callable $definition, ?string $tag = null): self;
 
     public function config(object $config): self;
 
@@ -19,7 +19,7 @@ public function config(object $config): self;
      * @param class-string<TClassName> $className
      * @return TClassName
      */
-    public function get(string $className, mixed ...$params): object;
+    public function get(string $className, ?string $tag = null, mixed ...$params): object;
 
     public function call(object $object, string $methodName, mixed ...$params): mixed;
 
diff --git a/src/Container/Dependency.php b/src/Container/Dependency.php
index 22c7b70..a8079b8 100644
--- a/src/Container/Dependency.php
+++ b/src/Container/Dependency.php
@@ -41,6 +41,12 @@ public function getTypeName(): string
     {
         $dependency = $this->dependency;
 
+        if (is_string($dependency)) {
+            $parts = explode('\\', $dependency);
+
+            return $parts[array_key_last($parts)];
+        }
+
         return match($dependency::class) {
             ReflectionClass::class => $dependency->getShortName(),
             ReflectionMethod::class => $dependency->getDeclaringClass()->getShortName(),
diff --git a/src/Container/Exceptions/CannotResolveTaggedDependency.php b/src/Container/Exceptions/CannotResolveTaggedDependency.php
new file mode 100644
index 0000000..ea3f0b5
--- /dev/null
+++ b/src/Container/Exceptions/CannotResolveTaggedDependency.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Container\Exceptions;
+
+use Exception;
+use Tempest\Container\Dependency;
+use Tempest\Container\DependencyChain;
+
+final class CannotResolveTaggedDependency extends Exception
+{
+    public function __construct(DependencyChain $chain, Dependency $brokenDependency, string $tag)
+    {
+        $stack = $chain->all();
+        $stack[] = $brokenDependency;
+
+        $message = PHP_EOL . PHP_EOL. "Could not resolve tagged dependency {$brokenDependency->getName()}#{$tag}, did you forget to define an initializer for it?" . PHP_EOL;
+
+        if (count($stack) < 2) {
+            parent::__construct($message);
+
+            return;
+        }
+
+        $i = 0;
+
+        foreach ($stack as $currentDependency) {
+            $pipe = match ($i) {
+                0 => '┌──',
+                count($stack) - 1 => '└──',
+                default => '├──',
+            };
+
+            $message .= PHP_EOL . "\t{$pipe} " . $currentDependency->getShortName();
+
+            $i++;
+        }
+
+        $selectionLine = preg_replace_callback(
+            pattern: '/(?<prefix>(.*))(?<selection>'. $brokenDependency->getTypeName() .'\s\$\w+)(.*)/',
+            callback: function ($matches) {
+                return str_repeat(' ', strlen($matches['prefix']) + 4)
+                    . str_repeat('▒', strlen($matches['selection']));
+            },
+            subject: $chain->last()->getShortName(),
+        );
+
+        $message .= PHP_EOL;
+        $message .= "\t{$selectionLine}";
+        $message .= PHP_EOL;
+        $message .= "Originally called in {$chain->getOrigin()}";
+        $message .= PHP_EOL;
+
+        parent::__construct($message);
+    }
+}
diff --git a/src/Container/GenericContainer.php b/src/Container/GenericContainer.php
index 1335a08..d44eb35 100644
--- a/src/Container/GenericContainer.php
+++ b/src/Container/GenericContainer.php
@@ -14,6 +14,7 @@
 use ReflectionUnionType;
 use Tempest\Container\Exceptions\CannotAutowireException;
 use Tempest\Container\Exceptions\CannotInstantiateDependencyException;
+use Tempest\Container\Exceptions\CannotResolveTaggedDependency;
 use Tempest\Support\Reflection\Attributes;
 use Throwable;
 
@@ -56,8 +57,10 @@ public function register(string $className, callable $definition): self
         return $this;
     }
 
-    public function singleton(string $className, object|callable $definition): self
+    public function singleton(string $className, object|callable $definition, ?string $tag = null): self
     {
+        $className = $this->resolveTaggedName($className, $tag);
+
         $this->singletons[$className] = $definition;
 
         return $this;
@@ -70,11 +73,15 @@ public function config(object $config): self
         return $this;
     }
 
-    public function get(string $className, mixed ...$params): object
+    public function get(string $className, ?string $tag = null, mixed ...$params): object
     {
         $this->resolveChain();
 
-        $dependency = $this->resolve($className, ...$params);
+        $dependency = $this->resolve(
+            className: $className,
+            tag: $tag,
+            params: $params,
+        );
 
         $this->stopChain();
 
@@ -110,9 +117,15 @@ public function addInitializer(ReflectionClass|string $initializerClass): Contai
             return $this;
         }
 
+        $initializeMethod = $initializerClass->getMethod('initialize');
+
+        // We resolve the optional Tag attribute from this initializer class
+        $tag = Attributes::find(Tag::class)->in($initializerClass)->first()
+            ?? Attributes::find(Tag::class)->in($initializeMethod)->first();
+
         // For normal Initializers, we'll use the return type
         // to determine which dependency they resolve
-        $returnTypes = $initializerClass->getMethod('initialize')->getReturnType();
+        $returnTypes = $initializeMethod->getReturnType();
 
         $returnTypes = match ($returnTypes::class) {
             ReflectionNamedType::class => [$returnTypes],
@@ -121,16 +134,18 @@ public function addInitializer(ReflectionClass|string $initializerClass): Contai
 
         /** @var ReflectionNamedType[] $returnTypes */
         foreach ($returnTypes as $returnType) {
-            $this->initializers[$returnType->getName()] = $initializerClass->getName();
+            $this->initializers[$this->resolveTaggedName($returnType->getName(), $tag?->name)] = $initializerClass->getName();
         }
 
         return $this;
     }
 
-    private function resolve(string $className, mixed ...$params): object
+    private function resolve(string $className, ?string $tag = null, mixed ...$params): object
     {
+        $dependencyName = $this->resolveTaggedName($className, $tag);
+
         // Check if the class has been registered as a singleton.
-        if ($instance = $this->singletons[$className] ?? null) {
+        if ($instance = $this->singletons[$dependencyName] ?? null) {
             if (is_callable($instance)) {
                 $instance = $instance($this);
                 $this->singletons[$className] = $instance;
@@ -142,14 +157,14 @@ private function resolve(string $className, mixed ...$params): object
         }
 
         // Check if a callable has been registered to resolve this class.
-        if ($definition = $this->definitions[$className] ?? null) {
+        if ($definition = $this->definitions[$dependencyName] ?? null) {
             $this->resolveChain()->add(new ReflectionFunction($definition));
 
             return $definition($this);
         }
 
         // Next we check if any of our default initializers can initialize this class.
-        if ($initializer = $this->initializerFor($className)) {
+        if ($initializer = $this->initializerFor($className, $tag)) {
             $this->resolveChain()->add(new ReflectionClass($initializer));
 
             $object = match (true) {
@@ -158,29 +173,34 @@ private function resolve(string $className, mixed ...$params): object
             };
 
             // Check whether the initializer's result should be registered as a singleton
-            if (Attributes::find(Singleton::class)->in($initializer::class)->first() !== null) {
-                $this->singleton($className, $object);
+            $singleton = Attributes::find(Singleton::class)->in($initializer::class)->first()
+                ?? Attributes::find(Singleton::class)->in((new ReflectionClass($initializer))->getMethod('initialize'))->first();
+
+            if ($singleton !== null) {
+                $this->singleton($className, $object, $tag);
             }
 
             return $object;
         }
 
+        // If we're requesting a tagged dependency and haven't resolved it at this point, something's wrong
+        if ($tag) {
+            throw new CannotResolveTaggedDependency($this->chain, new Dependency($className), $tag);
+        }
+
         // Finally, autowire the class.
         return $this->autowire($className, ...$params);
     }
 
-    private function initializerFor(string $className): null|Initializer|DynamicInitializer
+    private function initializerFor(string $className, ?string $tag = null): null|Initializer|DynamicInitializer
     {
         // Initializers themselves can't be initialized,
         // otherwise you'd end up with infinite loops
-        if (
-            is_a($className, Initializer::class, true)
-            || is_a($className, DynamicInitializer::class, true)
-        ) {
+        if (is_a($className, Initializer::class, true) || is_a($className, DynamicInitializer::class, true)) {
             return null;
         }
 
-        if ($initializerClass = $this->initializers[$className] ?? null) {
+        if ($initializerClass = $this->initializers[$this->resolveTaggedName($className, $tag)] ?? null) {
             return $this->resolve($initializerClass);
         }
 
@@ -233,8 +253,11 @@ private function autowireDependencies(ReflectionMethod $method, array $parameter
         // Build the class by iterating through its
         // dependencies and resolving them.
         foreach ($method->getParameters() as $parameter) {
+            $tag = Attributes::find(Tag::class)->in($parameter)->first();
+
             $dependencies[] = $this->clone()->autowireDependency(
                 parameter: $parameter,
+                tag: $tag?->name,
                 providedValue: $parameters[$parameter->getName()] ?? null,
             );
         }
@@ -242,7 +265,7 @@ private function autowireDependencies(ReflectionMethod $method, array $parameter
         return $dependencies;
     }
 
-    private function autowireDependency(ReflectionParameter $parameter, mixed $providedValue = null): mixed
+    private function autowireDependency(ReflectionParameter $parameter, ?string $tag, mixed $providedValue = null): mixed
     {
         $parameterType = $parameter->getType();
 
@@ -262,7 +285,12 @@ private function autowireDependency(ReflectionParameter $parameter, mixed $provi
         // Loop through each type until we hit a match.
         foreach ($types as $type) {
             try {
-                return $this->autowireObjectDependency($type, $providedValue);
+                return $this->autowireObjectDependency(
+                    /** @phpstan-ignore-next-line  */
+                    type: $type,
+                    tag: $tag,
+                    providedValue: $providedValue
+                );
             } catch (Throwable $throwable) {
                 // We were unable to resolve the dependency for the last union
                 // type, so we are moving on to the next one. We hang onto
@@ -282,7 +310,7 @@ private function autowireDependency(ReflectionParameter $parameter, mixed $provi
         throw $lastThrowable ?? new CannotAutowireException($this->chain, new Dependency($parameter));
     }
 
-    private function autowireObjectDependency(ReflectionNamedType $type, mixed $providedValue): mixed
+    private function autowireObjectDependency(ReflectionNamedType $type, ?string $tag, mixed $providedValue): mixed
     {
         // If the provided value is of the right type,
         // don't waste time autowiring, return it!
@@ -292,7 +320,7 @@ private function autowireObjectDependency(ReflectionNamedType $type, mixed $prov
 
         // If we can successfully retrieve an instance
         // of the necessary dependency, return it.
-        if ($instance = $this->resolve($type->getName())) {
+        if ($instance = $this->resolve(className: $type->getName(), tag: $tag)) {
             return $instance;
         }
 
@@ -361,4 +389,11 @@ public function __clone(): void
     {
         $this->chain = $this->chain?->clone();
     }
+
+    private function resolveTaggedName(string $className, ?string $tag): string
+    {
+        return $tag
+            ? "{$className}#{$tag}"
+            : $className;
+    }
 }
diff --git a/src/Container/Tag.php b/src/Container/Tag.php
new file mode 100644
index 0000000..322bac9
--- /dev/null
+++ b/src/Container/Tag.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tempest\Container;
+
+use Attribute;
+
+#[Attribute]
+final readonly class Tag
+{
+    public function __construct(public string $name)
+    {
+    }
+}
diff --git a/src/Support/Reflection/Attributes.php b/src/Support/Reflection/Attributes.php
index fa56a22..588ef96 100644
--- a/src/Support/Reflection/Attributes.php
+++ b/src/Support/Reflection/Attributes.php
@@ -7,12 +7,13 @@
 use ReflectionAttribute;
 use ReflectionClass;
 use ReflectionMethod;
+use ReflectionParameter;
 use ReflectionProperty;
 
 /** @template T */
 final class Attributes
 {
-    private ReflectionClass|ReflectionMethod|ReflectionProperty $reflector;
+    private ReflectionClass|ReflectionMethod|ReflectionProperty|ReflectionParameter $reflector;
 
     public function __construct(
         private readonly string $attributeName,
@@ -33,7 +34,7 @@ public static function find(string $attributeName): self
      * @param ReflectionClass|ReflectionMethod|ReflectionProperty $reflector
      * @return $this<T>
      */
-    public function in(ReflectionClass|ReflectionMethod|ReflectionProperty|string $reflector): self
+    public function in(ReflectionClass|ReflectionMethod|ReflectionProperty|ReflectionParameter|string $reflector): self
     {
         if (is_string($reflector)) {
             $reflector = new ReflectionClass($reflector);
diff --git a/tests/Unit/Container/ContainerTest.php b/tests/Unit/Container/ContainerTest.php
index 29ea0a9..f3c2883 100644
--- a/tests/Unit/Container/ContainerTest.php
+++ b/tests/Unit/Container/ContainerTest.php
@@ -5,6 +5,7 @@
 namespace Tests\Tempest\Unit\Container;
 
 use PHPUnit\Framework\TestCase;
+use Tempest\Container\Exceptions\CannotResolveTaggedDependency;
 use Tempest\Container\Exceptions\CircularDependencyException;
 use Tempest\Container\GenericContainer;
 use Tests\Tempest\Unit\Container\Fixtures\BuiltinArrayClass;
@@ -19,10 +20,14 @@
 use Tests\Tempest\Unit\Container\Fixtures\ContainerObjectDInitializer;
 use Tests\Tempest\Unit\Container\Fixtures\ContainerObjectE;
 use Tests\Tempest\Unit\Container\Fixtures\ContainerObjectEInitializer;
+use Tests\Tempest\Unit\Container\Fixtures\DependencyWithTaggedDependency;
 use Tests\Tempest\Unit\Container\Fixtures\IntersectionInitializer;
 use Tests\Tempest\Unit\Container\Fixtures\OptionalTypesClass;
 use Tests\Tempest\Unit\Container\Fixtures\SingletonClass;
 use Tests\Tempest\Unit\Container\Fixtures\SingletonInitializer;
+use Tests\Tempest\Unit\Container\Fixtures\TaggedDependency;
+use Tests\Tempest\Unit\Container\Fixtures\TaggedDependencyCliInitializer;
+use Tests\Tempest\Unit\Container\Fixtures\TaggedDependencyWebInitializer;
 use Tests\Tempest\Unit\Container\Fixtures\UnionImplementation;
 use Tests\Tempest\Unit\Container\Fixtures\UnionInitializer;
 use Tests\Tempest\Unit\Container\Fixtures\UnionInterfaceA;
@@ -208,4 +213,69 @@ public function test_circular_with_initializer_log(): void
             $this->assertStringContainsString(__FILE__, $e->getMessage());
         }
     }
+
+    public function test_tagged_singleton(): void
+    {
+        $container = new GenericContainer();
+
+        $container->singleton(
+            TaggedDependency::class,
+            new TaggedDependency('web'),
+            tag: 'web',
+        );
+
+        $container->singleton(
+            TaggedDependency::class,
+            new TaggedDependency('cli'),
+            tag: 'cli',
+        );
+
+        $this->assertSame('web', $container->get(TaggedDependency::class, 'web')->name);
+        $this->assertSame('cli', $container->get(TaggedDependency::class, 'cli')->name);
+    }
+
+    public function test_tagged_singleton_with_initializer(): void
+    {
+        $container = new GenericContainer();
+        $container->addInitializer(TaggedDependencyWebInitializer::class);
+        $container->addInitializer(TaggedDependencyCliInitializer::class);
+
+        $this->assertSame('web', $container->get(TaggedDependency::class, 'web')->name);
+        $this->assertSame('cli', $container->get(TaggedDependency::class, 'cli')->name);
+    }
+
+    public function test_tagged_singleton_exception(): void
+    {
+        $container = new GenericContainer();
+
+        $this->expectException(CannotResolveTaggedDependency::class);
+
+        $container->get(TaggedDependency::class, 'web');
+    }
+
+    public function test_autowired_tagged_dependency(): void
+    {
+        $container = new GenericContainer();
+        $container->addInitializer(TaggedDependencyWebInitializer::class);
+
+        $dependency = $container->get(DependencyWithTaggedDependency::class);
+        $this->assertSame('web', $dependency->dependency->name);
+    }
+
+    public function test_autowired_tagged_dependency_exception(): void
+    {
+        $container = new GenericContainer();
+
+        try {
+            $container->get(DependencyWithTaggedDependency::class);
+        } catch (CannotResolveTaggedDependency $exception) {
+            $this->assertStringContainsString(
+                <<<'TXT'
+	┌── DependencyWithTaggedDependency::__construct(TaggedDependency $dependency)
+	└── Tests\Tempest\Unit\Container\Fixtures\TaggedDependency
+TXT,
+                $exception->getMessage()
+            );
+        }
+    }
 }
diff --git a/tests/Unit/Container/Fixtures/DependencyWithTaggedDependency.php b/tests/Unit/Container/Fixtures/DependencyWithTaggedDependency.php
new file mode 100644
index 0000000..f0cb679
--- /dev/null
+++ b/tests/Unit/Container/Fixtures/DependencyWithTaggedDependency.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Unit\Container\Fixtures;
+
+use Tempest\Container\Tag;
+
+final readonly class DependencyWithTaggedDependency
+{
+    public function __construct(
+        #[Tag('web')]
+        public TaggedDependency $dependency,
+    ) {
+    }
+}
diff --git a/tests/Unit/Container/Fixtures/TaggedDependency.php b/tests/Unit/Container/Fixtures/TaggedDependency.php
new file mode 100644
index 0000000..abce07e
--- /dev/null
+++ b/tests/Unit/Container/Fixtures/TaggedDependency.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Unit\Container\Fixtures;
+
+final readonly class TaggedDependency
+{
+    public function __construct(public string $name)
+    {
+    }
+}
diff --git a/tests/Unit/Container/Fixtures/TaggedDependencyCliInitializer.php b/tests/Unit/Container/Fixtures/TaggedDependencyCliInitializer.php
new file mode 100644
index 0000000..572e74d
--- /dev/null
+++ b/tests/Unit/Container/Fixtures/TaggedDependencyCliInitializer.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Unit\Container\Fixtures;
+
+use Tempest\Container\Container;
+use Tempest\Container\Initializer;
+use Tempest\Container\Tag;
+
+#[Tag('cli')]
+final readonly class TaggedDependencyCliInitializer implements Initializer
+{
+    public function initialize(Container $container): TaggedDependency
+    {
+        return new TaggedDependency('cli');
+    }
+}
diff --git a/tests/Unit/Container/Fixtures/TaggedDependencyWebInitializer.php b/tests/Unit/Container/Fixtures/TaggedDependencyWebInitializer.php
new file mode 100644
index 0000000..db3ee7a
--- /dev/null
+++ b/tests/Unit/Container/Fixtures/TaggedDependencyWebInitializer.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Unit\Container\Fixtures;
+
+use Tempest\Container\Container;
+use Tempest\Container\Initializer;
+use Tempest\Container\Tag;
+
+#[Tag('web')]
+final readonly class TaggedDependencyWebInitializer implements Initializer
+{
+    public function initialize(Container $container): TaggedDependency
+    {
+        return new TaggedDependency('web');
+    }
+}