diff --git a/modules/core/src/main/scala/sangria/schema/Schema.scala b/modules/core/src/main/scala/sangria/schema/Schema.scala
index 6623f86a..38e234ce 100644
--- a/modules/core/src/main/scala/sangria/schema/Schema.scala
+++ b/modules/core/src/main/scala/sangria/schema/Schema.scala
@@ -1532,21 +1532,43 @@ case class Schema[Ctx, Val](
     }
   }
 
-  lazy val implementations: Map[String, Vector[ObjectType[_, _]]] =
-    allImplementations
-      .map { case (k, xs) =>
-        (
-          k,
-          xs.collect { case obj: ObjectType[_, _] =>
-            obj
-          })
-      }
-      .filter { case (_, v) =>
-        v.nonEmpty
-      }
+  def isPossibleImplementation(baseTypeName: String, tpe: ObjectLikeType[_, _]): Boolean =
+    tpe.name == baseTypeName || allImplementations
+      .get(baseTypeName)
+      .exists(_.exists(_.name == tpe.name))
+
+  @deprecated("Use concreteImplementations instead", "4.0.0")
+  lazy val implementations: Map[String, Vector[ObjectType[_, _]]] = concreteImplementations
+
+  lazy val concreteImplementations: Map[String, Vector[ObjectType[_, _]]] = allImplementations
+    .map { case (k, xs) =>
+      (
+        k,
+        xs.collect { case obj: ObjectType[_, _] =>
+          obj
+        })
+    }
+    .filter { case (_, v) =>
+      v.nonEmpty
+    }
 
+  /** This contains the map of all the concrete types by supertype.
+    *
+    * The supertype can be either a union or interface.
+    *
+    * According to the spec, even if an interface can implement another interface, this must only
+    * contains concrete types
+    *
+    * @see
+    *   https://spec.graphql.org/June2018/#sec-Union
+    * @see
+    *   https://spec.graphql.org/June2018/#sec-Interface
+    *
+    * @return
+    *   Map of subtype by supertype name
+    */
   lazy val possibleTypes: Map[String, Vector[ObjectType[_, _]]] =
-    implementations ++ unionTypes.values.map(ut => ut.name -> ut.types.toVector)
+    concreteImplementations ++ unionTypes.values.map(ut => ut.name -> ut.types.toVector)
 
   def isPossibleType(baseTypeName: String, tpe: ObjectType[_, _]): Boolean =
     possibleTypes.get(baseTypeName).exists(_.exists(_.name == tpe.name))
diff --git a/modules/core/src/main/scala/sangria/validation/TypeComparators.scala b/modules/core/src/main/scala/sangria/validation/TypeComparators.scala
index c8d460af..46d4b59a 100644
--- a/modules/core/src/main/scala/sangria/validation/TypeComparators.scala
+++ b/modules/core/src/main/scala/sangria/validation/TypeComparators.scala
@@ -22,7 +22,10 @@ object TypeComparators {
       case (sub, OptionInputType(ofType2)) => isSubType(schema, sub, ofType2)
       case (ListType(ofType1), ListType(ofType2)) => isSubType(schema, ofType1, ofType2)
       case (ListInputType(ofType1), ListInputType(ofType2)) => isSubType(schema, ofType1, ofType2)
-      case (t1: ObjectType[_, _], t2: AbstractType) => schema.isPossibleType(t2.name, t1)
+      case (t1: ObjectType[_, _], t2: AbstractType) =>
+        schema.isPossibleType(t2.name, t1)
+      case (t1: InterfaceType[_, _], t2: AbstractType) =>
+        schema.isPossibleImplementation(t2.name, t1)
       case (t1: Named, t2: Named) => t1.name == t2.name
       case _ => false
     }
diff --git a/modules/derivation/src/test/scala/sangria/schema/SchemaConstraintsSpec.scala b/modules/derivation/src/test/scala/sangria/schema/SchemaConstraintsSpec.scala
index cb79bb03..aa1e155e 100644
--- a/modules/derivation/src/test/scala/sangria/schema/SchemaConstraintsSpec.scala
+++ b/modules/derivation/src/test/scala/sangria/schema/SchemaConstraintsSpec.scala
@@ -971,6 +971,84 @@ class SchemaConstraintsSpec extends AnyWordSpec with Matchers {
         }
       """)
 
+    "rejects an Interface with a differently typed Interface field" in invalidSchema(
+      graphql"""
+        type Query {
+          test: AnotherObject
+        }
+
+        type A { foo: String }
+        type B { foo: String }
+
+        interface AnotherInterface {
+          field: A
+        }
+
+        type AnotherObject implements AnotherInterface {
+          field: B
+        }
+      """,
+      "AnotherInterface.field expects type 'A', but AnotherObject.field provides type 'B'." -> Seq(
+        Pos(14, 11),
+        Pos(10, 11))
+    )
+
+    "accepts an Interface with a subtyped Interface field (interface)" in validSchema(graphql"""
+        type Query {
+          test: Foo
+        }
+
+        interface Node {
+          id: ID!
+        }
+
+        interface Edge {
+          cursor: String!
+          node: Node!
+        }
+
+        interface Foo implements Node {
+          id: ID!
+        }
+
+        type ConcreteFoo implements Foo & Node {
+          id: ID!
+        }
+
+        type FooEdge implements Edge {
+          cursor: String!
+          node: Foo!
+        }
+
+        type Test {
+          fooEdge: FooEdge
+        }
+      """)
+
+    "accepts an Interface with a subtyped Interface field (union)" in validSchema(graphql"""
+        type Query {
+          fooBar: FooBar
+        }
+
+        type SomeObject {
+          field: String
+        }
+
+        union SomeUnionType = SomeObject
+
+        interface Foo {
+          foo: SomeUnionType
+        }
+
+        interface Bar implements Foo {
+          foo: SomeUnionType
+        }
+
+        type FooBar implements Foo & Bar {
+          test: String
+        }
+      """)
+
     "rejects an Interface missing an Interface argument" in invalidSchema(
       graphql"""
         type Query {
@@ -995,6 +1073,29 @@ class SchemaConstraintsSpec extends AnyWordSpec with Matchers {
       )
     )
 
+    "rejects an Interface with an incorrectly typed Interface argument" in invalidSchema(
+      graphql"""
+        type Query {
+          fooBar: FooBar
+        }
+
+        interface Foo {
+          foo(input: String): String
+        }
+
+        interface Bar implements Foo {
+          foo(input: Int): String
+        }
+
+        type FooBar implements Foo & Bar {
+          test: Int
+        }
+      """,
+      "Foo.foo(input) expects type 'String', but Bar.foo(input) provides type 'Int'." -> Seq(
+        Pos(7, 15),
+        Pos(11, 15))
+    )
+
     "rejects an Interface with an incorrectly typed Interface field" in invalidSchema(
       graphql"""
         type Query {