diff --git a/immer/map.hpp b/immer/map.hpp
index cab8e5d5..7cefdce8 100644
--- a/immer/map.hpp
+++ b/immer/map.hpp
@@ -158,7 +158,7 @@ class map
     using mapped_type     = T;
     using value_type      = std::pair<K, T>;
     using size_type       = detail::hamts::size_t;
-    using diference_type  = std::ptrdiff_t;
+    using difference_type  = std::ptrdiff_t;
     using hasher          = Hash;
     using key_equal       = Equal;
     using reference       = const value_type&;
diff --git a/immer/map_transient.hpp b/immer/map_transient.hpp
index 935f48e2..6462446f 100644
--- a/immer/map_transient.hpp
+++ b/immer/map_transient.hpp
@@ -51,7 +51,7 @@ class map_transient : MemoryPolicy::transience_t::owner
     using mapped_type     = T;
     using value_type      = std::pair<K, T>;
     using size_type       = detail::hamts::size_t;
-    using diference_type  = std::ptrdiff_t;
+    using difference_type  = std::ptrdiff_t;
     using hasher          = Hash;
     using key_equal       = Equal;
     using reference       = const value_type&;
diff --git a/immer/set.hpp b/immer/set.hpp
index df4192f5..2bddc043 100644
--- a/immer/set.hpp
+++ b/immer/set.hpp
@@ -73,7 +73,7 @@ class set
 public:
     using value_type      = T;
     using size_type       = detail::hamts::size_t;
-    using diference_type  = std::ptrdiff_t;
+    using difference_type  = std::ptrdiff_t;
     using hasher          = Hash;
     using key_equal       = Equal;
     using reference       = const T&;
diff --git a/immer/set_transient.hpp b/immer/set_transient.hpp
index e07668e2..0eb5914a 100644
--- a/immer/set_transient.hpp
+++ b/immer/set_transient.hpp
@@ -40,7 +40,7 @@ class set_transient : MemoryPolicy::transience_t::owner
 
     using value_type      = T;
     using size_type       = detail::hamts::size_t;
-    using diference_type  = std::ptrdiff_t;
+    using difference_type  = std::ptrdiff_t;
     using hasher          = Hash;
     using key_equal       = Equal;
     using reference       = const T&;
diff --git a/immer/table.hpp b/immer/table.hpp
index 0e977c6a..77eaef01 100644
--- a/immer/table.hpp
+++ b/immer/table.hpp
@@ -193,7 +193,7 @@ class table
     using mapped_type     = T;
     using value_type      = T;
     using size_type       = detail::hamts::size_t;
-    using diference_type  = std::ptrdiff_t;
+    using difference_type  = std::ptrdiff_t;
     using hasher          = Hash;
     using key_equal       = Equal;
     using reference       = const value_type&;
diff --git a/immer/table_transient.hpp b/immer/table_transient.hpp
index 30b0a8c6..c94599b3 100644
--- a/immer/table_transient.hpp
+++ b/immer/table_transient.hpp
@@ -42,7 +42,7 @@ class table_transient : MemoryPolicy::transience_t::owner
     using mapped_type     = T;
     using value_type      = T;
     using size_type       = detail::hamts::size_t;
-    using diference_type  = std::ptrdiff_t;
+    using difference_type  = std::ptrdiff_t;
     using hasher          = Hash;
     using key_equal       = Equal;
     using reference       = const value_type&;