diff --git a/CHANGES/828.contrib.rst b/CHANGES/828.contrib.rst
new file mode 100644
index 000000000..2632e285a
--- /dev/null
+++ b/CHANGES/828.contrib.rst
@@ -0,0 +1,8 @@
+Added an explicit ``void`` for arguments in C-function signatures
+which addresses the following compiler warning:
+
+.. code-block:: console
+
+   warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
+
+-- by :user:`hoodmane`
diff --git a/multidict/_multidict.c b/multidict/_multidict.c
index bcb37137f..5121862c7 100644
--- a/multidict/_multidict.c
+++ b/multidict/_multidict.c
@@ -1695,7 +1695,7 @@ static PyModuleDef multidict_module = {
 };
 
 PyMODINIT_FUNC
-PyInit__multidict()
+PyInit__multidict(void)
 {
 #if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 9
     multidict_str_lower = PyUnicode_InternFromString("lower");
diff --git a/multidict/_multilib/iter.h b/multidict/_multilib/iter.h
index 4e2e32b38..9ee337538 100644
--- a/multidict/_multilib/iter.h
+++ b/multidict/_multilib/iter.h
@@ -222,7 +222,7 @@ static PyTypeObject multidict_keys_iter_type = {
 };
 
 static inline int
-multidict_iter_init()
+multidict_iter_init(void)
 {
     if (PyType_Ready(&multidict_items_iter_type) < 0 ||
         PyType_Ready(&multidict_values_iter_type) < 0 ||
diff --git a/multidict/_multilib/views.h b/multidict/_multilib/views.h
index 5b1ebfe77..ad94b21ba 100644
--- a/multidict/_multilib/views.h
+++ b/multidict/_multilib/views.h
@@ -385,7 +385,7 @@ static PyTypeObject multidict_valuesview_type = {
 
 
 static inline int
-multidict_views_init()
+multidict_views_init(void)
 {
     PyObject *reg_func_call_result = NULL;
     PyObject *module = PyImport_ImportModule("multidict._multidict_base");