diff --git a/doc/lispref/package.texi b/doc/lispref/package.texi
index 236855bdf8..a8a136f187 100644
--- a/doc/lispref/package.texi
+++ b/doc/lispref/package.texi
@@ -109,7 +109,7 @@ Packaging Basics
 @code{package-activate-all} to make installed packages available to the
 current session.  This is done after loading the early init file, but
 before loading the regular init file (@pxref{Startup Summary}).
-Packages are not automatically made available if the user option
+Packages are not automatically made available if the variable
 @code{package-enable-at-startup} is set to @code{nil} in the early
 init file.
 
diff --git a/etc/NEWS b/etc/NEWS
index 033cb48978..fa681f3f47 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -191,6 +191,9 @@ it won't work right without some adjustment:
   does not need to pay attention to 'package-load-list' or
   'package-user-dir' any more.
 
+The value of 'package-enable-at-startup' can no longer be changed
+using customize.
+
 ---
 ** Emacs now notifies systemd when startup finishes or shutdown begins.
 Units that are ordered after 'emacs.service' will only be started
diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 539b236b63..2885b2c194 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -162,20 +162,23 @@ package
 ;;; Customization options
 
 ;;;###autoload
-(defcustom package-enable-at-startup t
+(defvar package-enable-at-startup t
   "Whether to make installed packages available when Emacs starts.
 If non-nil, packages are made available before reading the init
 file (but after reading the early init file).  This means that if
-you wish to set this variable, you must do so in the early init
-file.  Regardless of the value of this variable, packages are not
-made available if `user-init-file' is nil (e.g. Emacs was started
-with \"-q\").
+you wish to set this variable to nil, you must do that in the
+early init file.  See Info node `(emacs) Early Init File'.
+
+Note that the package system will automatically set this variable
+to nil when the package system is initialized.
+
+Regardless of the value of this variable, packages are not made
+available if `user-init-file' is nil (e.g. Emacs was started with
+\"-q\").
 
 Even if the value is nil, you can type \\[package-initialize] to
 make installed packages available at any time, or you can
-call (package-initialize) in your init-file."
-  :type 'boolean
-  :version "24.1")
+call (package-initialize) in your init-file.")
 
 (defcustom package-load-list '(all)
   "List of packages for `package-initialize' to make available.