diff --git a/modules/core/src/main/scala/compiler.scala b/modules/core/src/main/scala/compiler.scala
index 55c5281a..32fbca3d 100644
--- a/modules/core/src/main/scala/compiler.scala
+++ b/modules/core/src/main/scala/compiler.scala
@@ -794,7 +794,10 @@ object QueryCompiler {
           for {
             s      <- Elab.schema
             c      <- Elab.context
-            subtpe <- Elab.liftR(Result.fromOption(s.definition(tpnme), s"Unknown type '$tpnme' in type condition"))
+            subtpe <- Elab.liftR(Result.fromOption(
+                        s.definition(tpnme).orElse(Introspection.schema.definition(tpnme)),
+                        s"Unknown type '$tpnme' in type condition of inline fragment"
+                      ))
             _      <- Elab.push(c.asType(subtpe), child)
             ec     <- transform(child)
             _      <- Elab.pop
@@ -997,7 +1000,7 @@ object QueryCompiler {
                           case None =>
                             Elab.pure(ctpe)
                           case Some(tpnme) =>
-                            Elab.liftR(s.definition(tpnme).toResult(s"Unknown type '$tpnme' in type condition inline fragment"))
+                            Elab.liftR(s.definition(tpnme).toResult(s"Unknown type '$tpnme' in type condition of inline fragment"))
                         }
               _      <- Elab.failure(s"Inline fragment with type condition '$subtpe' is not compatible with type '$ctpe'").whenA(!fragmentApplies(s, subtpe, ctpe))
               _      <- Elab.push(c.asType(subtpe), child)
diff --git a/modules/core/src/test/scala/introspection/IntrospectionSuite.scala b/modules/core/src/test/scala/introspection/IntrospectionSuite.scala
index 397adf4b..a8840aa3 100644
--- a/modules/core/src/test/scala/introspection/IntrospectionSuite.scala
+++ b/modules/core/src/test/scala/introspection/IntrospectionSuite.scala
@@ -1288,6 +1288,43 @@ final class IntrospectionSuite extends CatsEffectSuite {
     assertIO(res, Some(expected))
   }
 
+  test("introspection types in inline fragments") {
+    val query = """
+      query IntrospectionQuery {
+        __type(name: "User") {
+          ...TypeRef
+        }
+      }
+
+      fragment TypeRef on __Type {
+        name
+        kind
+        ofType {
+          name
+          ... on __Type {
+            kind
+          }
+        }
+      }
+    """
+
+    val expected = json"""
+      {
+        "data" : {
+          "__type" : {
+            "name" : "User",
+            "kind" : "OBJECT",
+            "ofType" : null
+          }
+        }
+      }
+    """
+
+    val res = SmallMapping.compileAndRun(query)
+
+    assertIO(res, expected)
+  }
+
   test("typename query") {
     val query = """
       {