diff --git a/autoload/ale/completion.vim b/autoload/ale/completion.vim
index 142c2e89..945dc2dd 100644
--- a/autoload/ale/completion.vim
+++ b/autoload/ale/completion.vim
@@ -6,6 +6,7 @@ scriptencoding utf-8
 " only valid in Insert mode. This way, feedkeys() won't send these keys if you
 " quit Insert mode quickly enough.
 inoremap <silent> <Plug>(ale_show_completion_menu) <C-x><C-o><C-p>
+inoremap <silent> <Plug>(ale_stop_completion_menu) <C-x><C-z>
 " If we hit the key sequence in normal mode, then we won't show the menu, so
 " we should restore the old settings right away.
 nnoremap <silent> <Plug>(ale_show_completion_menu) :call ale#completion#RestoreCompletionOptions()<CR>
@@ -133,6 +134,7 @@ let s:should_complete_map = {
 \   'typescript': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$|''$|"$',
 \   'rust': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$|::$',
 \   'cpp': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$|::$|-\>$',
+\   'c': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$|-\>$',
 \}
 
 " Regular expressions for finding the start column to replace with completion.
@@ -148,6 +150,7 @@ let s:trigger_character_map = {
 \   'typescript': ['.', '''', '"'],
 \   'rust': ['.', '::'],
 \   'cpp': ['.', '::', '->'],
+\   'c': ['.', '->'],
 \}
 
 function! s:GetFiletypeValue(map, filetype) abort
@@ -978,6 +981,14 @@ function! ale#completion#StopTimer() abort
     let s:timer_id = -1
 endfunction
 
+" Close the previous completion menu (if any), so that the newer autocompletion
+" candidates will show up
+function! s:closePreviousCompletionMenu() abort
+    if exists('*complete_info') && !empty(complete_info(['mode']))
+        call ale#util#FeedKeys("\<Plug>(ale_stop_completion_menu)")
+    endif
+endfunction
+
 function! ale#completion#Queue() abort
     if !get(b:, 'ale_completion_enabled', g:ale_completion_enabled)
         return
@@ -999,6 +1010,8 @@ function! ale#completion#Queue() abort
 
     call ale#completion#StopTimer()
 
+    call s:closePreviousCompletionMenu()
+
     let s:timer_id = timer_start(g:ale_completion_delay, function('s:TimerHandler'))
 endfunction
 
diff --git a/rplugin/python3/deoplete/sources/ale.py b/rplugin/python3/deoplete/sources/ale.py
index 82d9bbf2..a692dc31 100644
--- a/rplugin/python3/deoplete/sources/ale.py
+++ b/rplugin/python3/deoplete/sources/ale.py
@@ -32,6 +32,7 @@ class Source(Base):
             'rust': r'(\.|::)\w*$',
             'typescript': r'(\.|\'|")\w*$',
             'cpp': r'(\.|::|->)\w*$',
+            'c': r'(\.|->)\w*$',
         }
 
     # Returns an integer for the start position, as with omnifunc.
diff --git a/test/python/test_deoplete_source.py b/test/python/test_deoplete_source.py
index 8304fa25..74a42dc2 100644
--- a/test/python/test_deoplete_source.py
+++ b/test/python/test_deoplete_source.py
@@ -53,6 +53,7 @@ class DeopleteSourceTest(unittest.TestCase):
                 'rust': r'(\.|::)\w*$',
                 'typescript': r'(\.|\'|")\w*$',
                 'cpp': r'(\.|::|->)\w*$',
+                'c': r'(\.|->)\w*$',
             },
             'is_bytepos': True,
             'is_volatile': True,