diff --git a/spec/Section 2 -- Source Schema.md b/spec/Section 2 -- Source Schema.md
index 9576f0d..6d42476 100644
--- a/spec/Section 2 -- Source Schema.md	
+++ b/spec/Section 2 -- Source Schema.md	
@@ -112,7 +112,7 @@ type Clothing @key(fields: "id") {
 ```
 
 If the lookup returns an interface, the interface must also be annotated with a
-`@key` directive and declare it's keys.
+`@key` directive and declare its keys.
 
 ```graphql example
 interface Node @key(fields: "id") {