diff --git a/completions/bash/brew b/completions/bash/brew
index 5bd972d729782..2ffe7b40fc0a4 100644
--- a/completions/bash/brew
+++ b/completions/bash/brew
@@ -799,6 +799,7 @@ _brew_determine_test_runners() {
   case "${cur}" in
     -*)
       __brewcomp "
+      --all-supported
       --debug
       --dependents
       --eval-all
diff --git a/completions/fish/brew.fish b/completions/fish/brew.fish
index c7bb873e439c1..7e766304b5653 100644
--- a/completions/fish/brew.fish
+++ b/completions/fish/brew.fish
@@ -609,6 +609,7 @@ __fish_brew_complete_arg 'desc; and not __fish_seen_argument -l formula -l formu
 
 
 __fish_brew_complete_cmd 'determine-test-runners' 'Determines the runners used to test formulae or their dependents'
+__fish_brew_complete_arg 'determine-test-runners' -l all-supported -d 'Instead of selecting runners based on the chosen formula, return all supported runners'
 __fish_brew_complete_arg 'determine-test-runners' -l debug -d 'Display any debugging information'
 __fish_brew_complete_arg 'determine-test-runners' -l dependents -d 'Determine runners for testing dependents. Requires `--eval-all` or `HOMEBREW_EVAL_ALL`'
 __fish_brew_complete_arg 'determine-test-runners' -l eval-all -d 'Evaluate all available formulae, whether installed or not, to determine testing dependents'
diff --git a/completions/zsh/_brew b/completions/zsh/_brew
index 334445c60bad9..bc499bbf7f34a 100644
--- a/completions/zsh/_brew
+++ b/completions/zsh/_brew
@@ -768,8 +768,9 @@ _brew_desc() {
 # brew determine-test-runners
 _brew_determine_test_runners() {
   _arguments \
+    '(--dependents)--all-supported[Instead of selecting runners based on the chosen formula, return all supported runners]' \
     '--debug[Display any debugging information]' \
-    '--dependents[Determine runners for testing dependents. Requires `--eval-all` or `HOMEBREW_EVAL_ALL`]' \
+    '(--all-supported)--dependents[Determine runners for testing dependents. Requires `--eval-all` or `HOMEBREW_EVAL_ALL`]' \
     '--eval-all[Evaluate all available formulae, whether installed or not, to determine testing dependents]' \
     '--help[Show this message]' \
     '--quiet[Make some output more quiet]' \