diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 427602055c..ba6592eba5 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -127,6 +127,17 @@ then
   HOMEBREW_CACHE="${HOMEBREW_CACHE:-${HOME}/Library/Caches/Homebrew}"
   HOMEBREW_LOGS="${HOMEBREW_LOGS:-${HOME}/Library/Logs/Homebrew}"
   HOMEBREW_SYSTEM_TEMP="/private/tmp"
+
+  # Set a variable when the macOS system Ruby is new enough to avoid spawning
+  # a Ruby process unnecessarily.
+  if [[ "$HOMEBREW_MACOS_VERSION_NUMERIC" -lt "101303" ]]
+  then
+    unset HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH
+  else
+    # Used in ruby.sh.
+    # shellcheck disable=SC2034
+    HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH="1"
+  fi
 else
   HOMEBREW_PROCESSOR="$(uname -m)"
   HOMEBREW_PRODUCT="${HOMEBREW_SYSTEM}brew"
@@ -157,6 +168,8 @@ else
   HOMEBREW_CACHE="${HOMEBREW_CACHE:-${CACHE_HOME}/Homebrew}"
   HOMEBREW_LOGS="${HOMEBREW_LOGS:-${CACHE_HOME}/Homebrew/Logs}"
   HOMEBREW_SYSTEM_TEMP="/tmp"
+
+  unset HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH
 fi
 
 if [[ -n "$HOMEBREW_MACOS" || -n "$HOMEBREW_FORCE_HOMEBREW_ON_LINUX" ]]
diff --git a/Library/Homebrew/utils/ruby.sh b/Library/Homebrew/utils/ruby.sh
index 6aff2185a8..b1a2988505 100644
--- a/Library/Homebrew/utils/ruby.sh
+++ b/Library/Homebrew/utils/ruby.sh
@@ -35,7 +35,10 @@ setup-ruby-path() {
         HOMEBREW_RUBY_PATH="$(type -P ruby)"
       fi
 
-      if [[ -n "$HOMEBREW_RUBY_PATH" && -z "$HOMEBREW_FORCE_VENDOR_RUBY" ]]
+      if [[ -n "$HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH" ]]
+      then
+        ruby_version_new_enough="true"
+      elif [[ -n "$HOMEBREW_RUBY_PATH" && -z "$HOMEBREW_FORCE_VENDOR_RUBY" ]]
       then
         ruby_version_new_enough="$("$HOMEBREW_RUBY_PATH" --disable=gems -rrubygems -e "puts Gem::Version.new(RUBY_VERSION.to_s.dup) >= Gem::Version.new('$minimum_ruby_version')")"
       fi