diff --git a/AK/NonnullOwnPtr.h b/AK/NonnullOwnPtr.h
index 7c8c7817f2..e9cc114be6 100644
--- a/AK/NonnullOwnPtr.h
+++ b/AK/NonnullOwnPtr.h
@@ -18,6 +18,8 @@ class WeakPtr;
 template<typename T>
 class CONSUMABLE(unconsumed) NonnullOwnPtr {
 public:
+    typedef T ElementType;
+
     enum AdoptTag { Adopt };
 
     RETURN_TYPESTATE(unconsumed)
diff --git a/AK/NonnullOwnPtrVector.h b/AK/NonnullOwnPtrVector.h
index d1d7024b7b..d00644225c 100644
--- a/AK/NonnullOwnPtrVector.h
+++ b/AK/NonnullOwnPtrVector.h
@@ -6,7 +6,7 @@
 namespace AK {
 
 template<typename T, int inline_capacity = 0>
-class NonnullOwnPtrVector : public NonnullPtrVector<NonnullOwnPtr<T>, T, inline_capacity>
+class NonnullOwnPtrVector : public NonnullPtrVector<NonnullOwnPtr<T>, inline_capacity>
 {
 };
 
diff --git a/AK/NonnullPtrVector.h b/AK/NonnullPtrVector.h
index 345da11e08..2cc7147c4a 100644
--- a/AK/NonnullPtrVector.h
+++ b/AK/NonnullPtrVector.h
@@ -4,8 +4,9 @@
 
 namespace AK {
 
-template<typename PtrType, typename T, int inline_capacity = 0>
+template<typename PtrType, int inline_capacity = 0>
 class NonnullPtrVector : public Vector<PtrType, inline_capacity> {
+    typedef typename PtrType::ElementType T;
     typedef Vector<PtrType, inline_capacity> Base;
 
 public:
diff --git a/AK/NonnullRefPtr.h b/AK/NonnullRefPtr.h
index 84719fd345..0cbb4ed8f9 100644
--- a/AK/NonnullRefPtr.h
+++ b/AK/NonnullRefPtr.h
@@ -26,9 +26,9 @@ inline void deref_if_not_null(T* ptr)
 template<typename T>
 class CONSUMABLE(unconsumed) NonnullRefPtr {
 public:
-    enum AdoptTag {
-        Adopt
-    };
+    typedef T ElementType;
+
+    enum AdoptTag { Adopt };
 
     RETURN_TYPESTATE(unconsumed)
     NonnullRefPtr(const T& object)
diff --git a/AK/NonnullRefPtrVector.h b/AK/NonnullRefPtrVector.h
index 1997e9fe45..38d137108b 100644
--- a/AK/NonnullRefPtrVector.h
+++ b/AK/NonnullRefPtrVector.h
@@ -6,7 +6,7 @@
 namespace AK {
 
 template<typename T, int inline_capacity = 0>
-class NonnullRefPtrVector : public NonnullPtrVector<NonnullRefPtr<T>, T, inline_capacity>
+class NonnullRefPtrVector : public NonnullPtrVector<NonnullRefPtr<T>, inline_capacity>
 {
 };