diff --git a/exercises/practice/simple-linked-list/.meta/example.cpp b/exercises/practice/simple-linked-list/.meta/example.cpp
index 45440ba6..0848ccf0 100644
--- a/exercises/practice/simple-linked-list/.meta/example.cpp
+++ b/exercises/practice/simple-linked-list/.meta/example.cpp
@@ -11,7 +11,7 @@ List::~List() {
     }
 }
 
-size_t List::size() const { return current_size; }
+std::size_t List::size() const { return current_size; }
 
 void List::push(int entry) {
     auto element = new Element{entry};
diff --git a/exercises/practice/simple-linked-list/.meta/example.h b/exercises/practice/simple-linked-list/.meta/example.h
index 5d79e6e3..f173515f 100644
--- a/exercises/practice/simple-linked-list/.meta/example.h
+++ b/exercises/practice/simple-linked-list/.meta/example.h
@@ -18,7 +18,7 @@ class List {
     List(List&&) = delete;
     List& operator=(List&&) = delete;
 
-    size_t size() const;
+    std::size_t size() const;
     void push(int entry);
     int pop();
     void reverse();
@@ -31,7 +31,7 @@ class List {
     };
 
     Element* head{nullptr};
-    size_t current_size{0};
+    std::size_t current_size{0};
 };
 
 }  // namespace simple_linked_list
diff --git a/exercises/practice/simple-linked-list/simple_linked_list.cpp b/exercises/practice/simple-linked-list/simple_linked_list.cpp
index 6574e342..2596f580 100644
--- a/exercises/practice/simple-linked-list/simple_linked_list.cpp
+++ b/exercises/practice/simple-linked-list/simple_linked_list.cpp
@@ -4,7 +4,7 @@
 
 namespace simple_linked_list {
 
-size_t List::size() const {
+std::size_t List::size() const {
     // TODO: Return the correct size of the list.
     return 0;
 }
diff --git a/exercises/practice/simple-linked-list/simple_linked_list.h b/exercises/practice/simple-linked-list/simple_linked_list.h
index 5d79e6e3..f173515f 100644
--- a/exercises/practice/simple-linked-list/simple_linked_list.h
+++ b/exercises/practice/simple-linked-list/simple_linked_list.h
@@ -18,7 +18,7 @@ class List {
     List(List&&) = delete;
     List& operator=(List&&) = delete;
 
-    size_t size() const;
+    std::size_t size() const;
     void push(int entry);
     int pop();
     void reverse();
@@ -31,7 +31,7 @@ class List {
     };
 
     Element* head{nullptr};
-    size_t current_size{0};
+    std::size_t current_size{0};
 };
 
 }  // namespace simple_linked_list