diff --git a/Library/Homebrew/completions/bash.erb b/Library/Homebrew/completions/bash.erb
index 55d2d13dc0..6bab42bbc6 100644
--- a/Library/Homebrew/completions/bash.erb
+++ b/Library/Homebrew/completions/bash.erb
@@ -59,7 +59,7 @@ __brew_complete_casks() {
 __brew_complete_installed_formulae() {
   local cur="${COMP_WORDS[COMP_CWORD]}"
   local installed_formulae
-  installed_formulae="$(command ls "$(brew --cellar)" 2>/dev/null)"
+  installed_formulae="$(command ls "${HOMEBREW_CELLAR:-$(brew --cellar)}" 2>/dev/null)"
   while read -r line; do COMPREPLY+=("${line}"); done < <(compgen -W "${installed_formulae}" -- "${cur}")
 }
 
diff --git a/completions/bash/brew b/completions/bash/brew
index abe94e31cf..1426bf06ff 100644
--- a/completions/bash/brew
+++ b/completions/bash/brew
@@ -46,7 +46,7 @@ __brew_complete_casks() {
 __brew_complete_installed_formulae() {
   local cur="${COMP_WORDS[COMP_CWORD]}"
   local installed_formulae
-  installed_formulae="$(command ls "$(brew --cellar)" 2>/dev/null)"
+  installed_formulae="$(command ls "${HOMEBREW_CELLAR:-$(brew --cellar)}" 2>/dev/null)"
   while read -r line; do COMPREPLY+=("${line}"); done < <(compgen -W "${installed_formulae}" -- "${cur}")
 }