diff --git a/Mk/Uses/completions.mk b/Mk/Uses/completions.mk
new file mode 100644
--- /dev/null
+++ b/Mk/Uses/completions.mk
@@ -0,0 +1,36 @@
+# Helper for programmable shell completions.
+#
+# Feature:	completions
+# Usage:	USES=completions OR USES=completions:ARGS
+# Valid ARGS:	(none), env
+#
+# none	Create the preliminary shell completion directories
+#	and expose the port variables.
+# env	Expose the port variables only.
+#
+# Variables, which can be used by the port:
+#
+# BASH_COMPDIR	Path to the bash completion directory.
+# FISH_COMPDIR	Path to the fish completion directory.
+# ZSH_COMPDIR	Path to the zsh completion directory.
+#
+# MAINTAINER: ports@FreeBSD.org
+
+.if !defined(_INCLUDE_USES_COMPLETIONS_MK)
+_INCLUDE_USES_COMPLETIONS_MK=	yes
+
+_valid_ARGS=	env
+.  for _arg in ${completions_ARGS}
+.    if !${_valid_ARGS:M${_arg}}
+IGNORE=		USES=completions: invalid argument: ${_arg}
+.    endif
+.  endfor
+
+BASH_COMPDIR?=	${PREFIX}/share/bash-completion/completions
+FISH_COMPDIR?=	${PREFIX}/share/fish/vendor_completions.d
+ZSH_COMPDIR?=	${PREFIX}/share/zsh/site-functions
+
+.  for shell in BASH FISH ZSH
+PLIST_SUB+=	${shell}_COMPDIR=${${shell}_COMPDIR:S,^${PREFIX}/,,}
+.  endfor
+.endif