diff --git a/libraries/AP_Math/vector2.cpp b/libraries/AP_Math/vector2.cpp
index 096d2e93ac..d8dd97bc88 100644
--- a/libraries/AP_Math/vector2.cpp
+++ b/libraries/AP_Math/vector2.cpp
@@ -119,7 +119,7 @@ bool Vector2<T>::operator ==(const Vector2<T> &v) const
 template <typename T>
 bool Vector2<T>::operator !=(const Vector2<T> &v) const
 {
-    return (x!=v.x && y!=v.y);
+    return (x!=v.x || y!=v.y);
 }
 
 template <typename T>
diff --git a/libraries/AP_Math/vector3.cpp b/libraries/AP_Math/vector3.cpp
index ae5399df32..8dfeff7f17 100644
--- a/libraries/AP_Math/vector3.cpp
+++ b/libraries/AP_Math/vector3.cpp
@@ -333,7 +333,7 @@ bool Vector3<T>::operator ==(const Vector3<T> &v) const
 template <typename T>
 bool Vector3<T>::operator !=(const Vector3<T> &v) const
 {
-    return (x!=v.x && y!=v.y && z!=v.z);
+    return (x!=v.x || y!=v.y || z!=v.z);
 }
 
 template <typename T>