diff --git a/Library/Homebrew/cmd/shellenv.sh b/Library/Homebrew/cmd/shellenv.sh
index 6e600df09d3ac..63e53774c5441 100644
--- a/Library/Homebrew/cmd/shellenv.sh
+++ b/Library/Homebrew/cmd/shellenv.sh
@@ -11,7 +11,7 @@
 
 # HOMEBREW_CELLAR and HOMEBREW_PREFIX are set by extend/ENV/super.rb
 # HOMEBREW_REPOSITORY is set by bin/brew
-# Trailing colon in MANPATH adds default man dirs to search path in Linux, does no harm in macOS.
+# Leading colon in MANPATH prepends default man dirs to search path in Linux and macOS.
 # Please do not submit PRs to remove it!
 # shellcheck disable=SC2154
 homebrew-shellenv() {
@@ -33,7 +33,7 @@ homebrew-shellenv() {
       echo "set -gx HOMEBREW_CELLAR \"${HOMEBREW_CELLAR}\";"
       echo "set -gx HOMEBREW_REPOSITORY \"${HOMEBREW_REPOSITORY}\";"
       echo "fish_add_path -gP \"${HOMEBREW_PREFIX}/bin\" \"${HOMEBREW_PREFIX}/sbin\";"
-      echo "! set -q MANPATH; and set MANPATH ''; set -gx MANPATH \"${HOMEBREW_PREFIX}/share/man\" \$MANPATH;"
+      echo "set -q MANPATH; and set MANPATH[1] \":\$(string trim --left --chars=\":\" \$MANPATH[1])\";"
       echo "! set -q INFOPATH; and set INFOPATH ''; set -gx INFOPATH \"${HOMEBREW_PREFIX}/share/info\" \$INFOPATH;"
       ;;
     csh | -csh | tcsh | -tcsh)
@@ -41,8 +41,8 @@ homebrew-shellenv() {
       echo "setenv HOMEBREW_CELLAR ${HOMEBREW_CELLAR};"
       echo "setenv HOMEBREW_REPOSITORY ${HOMEBREW_REPOSITORY};"
       echo "setenv PATH ${HOMEBREW_PREFIX}/bin:${HOMEBREW_PREFIX}/sbin:\$PATH;"
-      echo "setenv MANPATH ${HOMEBREW_PREFIX}/share/man\`[ \${?MANPATH} == 1 ] && echo \":\${MANPATH}\"\`:;"
-      echo "setenv INFOPATH ${HOMEBREW_PREFIX}/share/info\`[ \${?INFOPATH} == 1 ] && echo \":\${INFOPATH}\"\`;"
+      echo "if ( \${?MANPATH} == 1 ) setenv MANPATH :\${MANPATH};"
+      echo "setenv INFOPATH ${HOMEBREW_PREFIX}/share/info\`if ( \${?INFOPATH} == 1 ) echo \":\${INFOPATH}\"\`;"
       ;;
     pwsh | -pwsh | pwsh-preview | -pwsh-preview)
       echo "[System.Environment]::SetEnvironmentVariable('HOMEBREW_PREFIX','${HOMEBREW_PREFIX}',[System.EnvironmentVariableTarget]::Process)"
@@ -57,7 +57,7 @@ homebrew-shellenv() {
       echo "export HOMEBREW_CELLAR=\"${HOMEBREW_CELLAR}\";"
       echo "export HOMEBREW_REPOSITORY=\"${HOMEBREW_REPOSITORY}\";"
       echo "export PATH=\"${HOMEBREW_PREFIX}/bin:${HOMEBREW_PREFIX}/sbin\${PATH+:\$PATH}\";"
-      echo "export MANPATH=\"${HOMEBREW_PREFIX}/share/man\${MANPATH+:\$MANPATH}:\";"
+      echo "[ -z \"\${MANPATH}\" ] || export MANPATH=\":\${MANPATH#:}\";"
       echo "export INFOPATH=\"${HOMEBREW_PREFIX}/share/info:\${INFOPATH:-}\";"
       ;;
   esac