diff --git a/collects/planet2/lib.rkt b/collects/planet2/lib.rkt
index 8f88b397a0..856baa612f 100644
--- a/collects/planet2/lib.rkt
+++ b/collects/planet2/lib.rkt
@@ -667,11 +667,12 @@
   (dict-ref meta 'dependency empty))
 
 (define (update-packages in-pkgs
+                         #:all? [all? #f]
                          #:dep-behavior [dep-behavior #f]
                          #:deps? [deps? #f])
   (define pkgs
     (cond
-      [(empty? in-pkgs)
+      [(and all? (empty? in-pkgs))
        (filter update-is-possible? (hash-keys (read-pkg-db)))]
       [deps?
        (append-map
@@ -791,6 +792,7 @@
   [update-packages
    (->* ((listof string?))
         (#:dep-behavior dep-behavior/c
+                        #:all? boolean?
                         #:deps? boolean?)
         void)]
   [remove-packages
diff --git a/collects/planet2/main.rkt b/collects/planet2/main.rkt
index 286495129f..4123907b34 100644
--- a/collects/planet2/main.rkt
+++ b/collects/planet2/main.rkt
@@ -38,6 +38,7 @@
   "Update packages"
   [#:bool dont-setup () "Don't run 'raco setup' after changing packages (generally not a good idea)"]
   [#:bool installation ("-i") "Operate on the installation-wide package database"]
+  [#:bool all ("-a") "Update all packages (if no packages are given on the command line)"]
   [(#:sym #f) deps ()
    ("Specify the behavior for dependencies."
     "Options are: fail, force, search-ask, search-auto."
@@ -50,6 +51,7 @@
   (parameterize ([current-install-system-wide? installation])
     (with-package-lock
      (update-packages pkgs
+                      #:all? all
                       #:dep-behavior deps
                       #:deps? update-deps)
      (setup dont-setup)))]
diff --git a/collects/planet2/scribblings/planet2.scrbl b/collects/planet2/scribblings/planet2.scrbl
index e20c228f49..f2c867c2c8 100644
--- a/collects/planet2/scribblings/planet2.scrbl
+++ b/collects/planet2/scribblings/planet2.scrbl
@@ -157,8 +157,7 @@ sub-sub-commands:
 
 
 @item{@exec{update pkg ...} -- Checks the list of packages for
-@tech{package updates}. If no packages are given, checks every
-installed package. If an update is found, but it cannot be
+@tech{package updates}. If an update is found, but it cannot be
 installed (e.g. it is conflicted with another installed package), then
 this command fails atomically. It accepts the following options:
 
@@ -167,6 +166,8 @@ this command fails atomically. It accepts the following options:
  @item{@DFlag{installation} -- Same as for @exec{install}.}
  @item{@Flag{i} -- Same as for @exec{install}.}
  @item{@DFlag{deps} @exec{dep-behavior} -- Same as for @exec{install}.}
+ @item{@DFlag{all} -- Update all packages, if no packages are given in the argument list.}
+ @item{@Flag{a} -- Alias for @DFlag{all}.}
  @item{@DFlag{update-deps} -- Checks the named packages, and their dependencies (transitively) for updates.}
  ]
 }
diff --git a/collects/tests/planet2/tests-update-auto.rkt b/collects/tests/planet2/tests-update-auto.rkt
index 62e85ee5af..c5493eff9c 100644
--- a/collects/tests/planet2/tests-update-auto.rkt
+++ b/collects/tests/planet2/tests-update-auto.rkt
@@ -60,7 +60,7 @@
                       (file->string "test-pkgs/pkg-a-second.plt.CHECKSUM")
                       'source
                       "http://localhost:9999/pkg-a-second.plt"))
-   $ "raco pkg update" =exit> 0
+   $ "raco pkg update -a" =exit> 0
    $ "racket -e '(require pkg-a)'" =exit> 43
    $ "raco pkg remove pkg-b"
    $ "raco pkg show" =stdout> #rx"Package\\(auto\\?\\)    Checksum                                    Source\npkg-a\\*            [a-f0-9]+    \\(pns pkg-a\\)\n"
diff --git a/collects/tests/planet2/tests-update.rkt b/collects/tests/planet2/tests-update.rkt
index 6179cba459..458541d938 100644
--- a/collects/tests/planet2/tests-update.rkt
+++ b/collects/tests/planet2/tests-update.rkt
@@ -69,11 +69,11 @@
                      "http://localhost:9999/update-test/planet2-test1.zip"
                      "planet2-test1"
                      $ "raco pkg install test-pkgs/planet2-test2.zip"
-                     $ "raco pkg update" =exit> 0 =stdout> "No updates available\n"
+                     $ "raco pkg update -a" =exit> 0 =stdout> "No updates available\n"
                      $ "racket -e '(require planet2-test1/update)'" =exit> 42
                      $ "cp -f test-pkgs/planet2-test1-v2.zip test-pkgs/update-test/planet2-test1.zip"
                      $ "cp -f test-pkgs/planet2-test1-v2.zip.CHECKSUM test-pkgs/update-test/planet2-test1.zip.CHECKSUM"
-                     $ "raco pkg update" =exit> 0
+                     $ "raco pkg update -a" =exit> 0
                      $ "racket -e '(require planet2-test1/update)'" =exit> 43
                      $ "raco pkg remove planet2-test2")
     (finally