diff --git a/Library/Homebrew/completions/fish.erb b/Library/Homebrew/completions/fish.erb
index 85b250379d..f14ef8f2da 100644
--- a/Library/Homebrew/completions/fish.erb
+++ b/Library/Homebrew/completions/fish.erb
@@ -162,7 +162,7 @@ function __fish_brew_suggest_commands -d "Lists all commands names, including al
     end
 end
 
-function __fish_brew_suggest_diagnostic_check -d "List available diagnostic checks"
+function __fish_brew_suggest_diagnostic_checks -d "List available diagnostic checks"
     brew doctor --list-checks
 end
 
diff --git a/completions/fish/brew.fish b/completions/fish/brew.fish
index 49a3996a98..e033ba1806 100644
--- a/completions/fish/brew.fish
+++ b/completions/fish/brew.fish
@@ -149,7 +149,7 @@ function __fish_brew_suggest_commands -d "Lists all commands names, including al
     end
 end
 
-function __fish_brew_suggest_diagnostic_checks -d "List available diagnostic checks"
+function __fish_brew_suggest_diagnostic_check -d "List available diagnostic checks"
     brew doctor --list-checks
 end