diff --git a/.changeset/empty-planes-behave.md b/.changeset/empty-planes-behave.md
new file mode 100644
index 00000000..a7b23e43
--- /dev/null
+++ b/.changeset/empty-planes-behave.md
@@ -0,0 +1,5 @@
+---
+'@0no-co/graphqlsp': patch
+---
+
+Fix setting `shouldCheckForColocatedFragments` to `false` falling back to `true`
diff --git a/packages/graphqlsp/src/diagnostics.ts b/packages/graphqlsp/src/diagnostics.ts
index dde3d9c0..1be2507c 100644
--- a/packages/graphqlsp/src/diagnostics.ts
+++ b/packages/graphqlsp/src/diagnostics.ts
@@ -48,7 +48,7 @@ export function getGraphQLDiagnostics(
   const tagTemplate = info.config.template || 'gql';
   const scalars = info.config.scalars || {};
   const shouldCheckForColocatedFragments =
-    info.config.shouldCheckForColocatedFragments || true;
+    info.config.shouldCheckForColocatedFragments ?? true;
 
   let source = getSource(info, filename);
   if (!source) return undefined;