diff --git a/rewrite-json/src/main/java/org/openrewrite/json/AddKeyValue.java b/rewrite-json/src/main/java/org/openrewrite/json/AddKeyValue.java
new file mode 100644
index 00000000000..8c58c745d30
--- /dev/null
+++ b/rewrite-json/src/main/java/org/openrewrite/json/AddKeyValue.java
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2024 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.json;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Option;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.internal.ListUtils;
+import org.openrewrite.json.tree.Json;
+import org.openrewrite.json.tree.JsonKey;
+import org.openrewrite.json.tree.JsonRightPadded;
+import org.openrewrite.json.tree.Space;
+import org.openrewrite.marker.Markers;
+
+import java.util.Collections;
+import java.util.List;
+
+import static java.util.Collections.emptyList;
+import static org.openrewrite.Tree.randomId;
+
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class AddKeyValue extends Recipe {
+
+    @Option(displayName = "Key path",
+            description = "A JsonPath expression to locate the *parent* JSON entry.",
+            example = "'$.subjects.*' or '$.' or '$.x[1].y.*' etc.")
+    String keyPath;
+
+    @Option(displayName = "Key",
+            description = "The key to create.",
+            example = "myKey")
+    String key;
+
+    @Option(displayName = "Value",
+            description = "The value to add to the array at the specified key. Can be of any type." +
+                          " String values should be quoted to be inserted as Strings.",
+            example = "`\"myValue\"` or `{\"a\": 1}` or `[ 123 ]`")
+    String value;
+
+    @Option(displayName = "Prepend",
+            required = false,
+            description = "If set to `true` the value will be added to the beginning of the object")
+    boolean prepend;
+
+    @Override
+    public String getDisplayName() {
+        return "Add value to JSON Object";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Adds a `value` at the specified `keyPath` with the specified `key`, if the key doesn't already exist.";
+    }
+
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return new JsonIsoVisitor<ExecutionContext>() {
+            private final JsonPathMatcher pathMatcher = new JsonPathMatcher(keyPath);
+
+            @Override
+            public Json.JsonObject visitObject(Json.JsonObject obj, ExecutionContext ctx) {
+                obj = super.visitObject(obj, ctx);
+
+                if (pathMatcher.matches(getCursor()) && objectDoesNotContainKey(obj, key)) {
+                    List<Json> originalMembers = obj.getMembers();
+                    boolean jsonIsEmpty = originalMembers.isEmpty() || originalMembers.get(0) instanceof Json.Empty;
+                    Space space = jsonIsEmpty || prepend ? originalMembers.get(0).getPrefix() : Space.SINGLE_SPACE;
+
+                    JsonRightPadded<JsonKey> newKey = rightPaddedKey();
+                    Json.Literal newValue = valueLiteral();
+                    Json newMember = new Json.Member(randomId(), space, Markers.EMPTY, newKey, newValue);
+
+                    if (jsonIsEmpty) {
+                        return obj.withMembers(Collections.singletonList(newMember));
+                    }
+
+                    List<Json> newMembers = prepend ?
+                            ListUtils.concat(newMember, originalMembers) :
+                            ListUtils.concat(originalMembers, newMember);
+                    return obj.withMembers(newMembers);
+                }
+                return obj;
+            }
+
+            private Json.Literal valueLiteral() {
+                return new Json.Literal(randomId(), Space.SINGLE_SPACE, Markers.EMPTY, value, unQuote(value));
+            }
+
+            private JsonRightPadded<JsonKey> rightPaddedKey() {
+                return new JsonRightPadded<>(
+                        new Json.Literal(randomId(), Space.EMPTY, Markers.EMPTY, "\"" + key + "\"", key),
+                        Space.EMPTY, Markers.EMPTY
+                );
+            }
+
+            private String unQuote(String value) {
+                if (value.startsWith("'") || value.startsWith("\"")) {
+                    return value.substring(1, value.length() - 1);
+                }
+                return value;
+            }
+
+            private boolean objectDoesNotContainKey(Json.JsonObject obj, String key) {
+                for (Json member : obj.getMembers()) {
+                    if (member instanceof Json.Member) {
+                        if (keyMatches(((Json.Member) member).getKey(), key)) {
+                            return false;
+                        }
+                    }
+                }
+                return true;
+            }
+
+            private boolean keyMatches(JsonKey jsonKey, String key) {
+                if (jsonKey instanceof Json.Literal) {
+                    return key.equals(((Json.Literal) jsonKey).getValue());
+                } else if (jsonKey instanceof Json.Identifier) {
+                    return key.equals(((Json.Identifier) jsonKey).getName());
+                }
+                return false;
+            }
+        };
+    }
+}
diff --git a/rewrite-json/src/test/java/org/openrewrite/json/AddKeyValueTest.java b/rewrite-json/src/test/java/org/openrewrite/json/AddKeyValueTest.java
new file mode 100644
index 00000000000..32f20c3ef07
--- /dev/null
+++ b/rewrite-json/src/test/java/org/openrewrite/json/AddKeyValueTest.java
@@ -0,0 +1,182 @@
+/*
+ * Copyright 2024 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.json;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.json.Assertions.json;
+
+class AddKeyValueTest implements RewriteTest {
+
+    @Test
+    @DocumentExample
+    void shouldAppendSimpleValue() {
+        rewriteRun(
+          spec -> spec.recipe(new AddKeyValue("$.", "key", "\"val\"", false)),
+          //language=json
+          json(
+            """
+              {
+                  "x": "x",
+                  "l": [
+                      1, 2
+                  ]
+              }
+              """,
+            """
+              {
+                  "x": "x",
+                  "l": [
+                      1, 2
+                  ],
+                  "key": "val"
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void shouldAppendToNestedObject() {
+        rewriteRun(
+          spec -> spec.recipe(new AddKeyValue("$.x.y.*", "key", "\"val\"", false)),
+          //language=json
+          json(
+            """
+              {
+                  "x": {
+                      "y": { }
+                  }
+              }
+              """,
+            """
+              {
+                  "x": {
+                      "y": {"key": "val"}
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void shouldAppendToNestedObjectInArray() {
+        rewriteRun(
+          spec -> spec.recipe(new AddKeyValue("$.x[1].y.*", "key", "\"val\"", false)),
+          //language=json
+          json(
+            """
+              {
+                  "x": [
+                      { },
+                      {
+                          "y" : { }
+                      }
+                  ]
+              }
+              """,
+            """
+              {
+                  "x": [
+                      { },
+                      {
+                          "y" : {"key": "val"}
+                      }
+                  ]
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void shouldNotAppendIfExists() {
+        rewriteRun(
+          spec -> spec.recipe(new AddKeyValue("$.", "key", "\"val\"", false)),
+          //language=json
+          json(
+            """
+              {
+                  "key": "x"
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void shouldAppendObject() {
+        rewriteRun(
+          spec -> spec.recipe(new AddKeyValue(
+            "$.", "key", """
+                { "a": "b" }
+            """.trim(), false)),
+          //language=json
+          json(
+            """
+              {
+                  "x": "x",
+                  "l": [
+                      1, 2
+                  ]
+              }
+              """,
+            """
+              {
+                  "x": "x",
+                  "l": [
+                      1, 2
+                  ],
+                  "key": { "a": "b" }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void shouldPrependObject() {
+        rewriteRun(
+          spec -> spec.recipe(new AddKeyValue(
+            "$.", "key", """
+                { "a": "b" }
+            """.trim(), true)),
+          //language=json
+          json(
+            """
+              {
+                  "x": "x",
+                  "l": [
+                      1, 2
+                  ]
+              }
+              """,
+            """
+              {
+                  "key": { "a": "b" },
+                  "x": "x",
+                  "l": [
+                      1, 2
+                  ]
+              }
+              """
+          )
+        );
+    }
+}