diff --git a/Library/Homebrew/cmd/outdated.rb b/Library/Homebrew/cmd/outdated.rb
index ae065b1bcf..ec647d84c1 100644
--- a/Library/Homebrew/cmd/outdated.rb
+++ b/Library/Homebrew/cmd/outdated.rb
@@ -3,6 +3,8 @@
 require "formula"
 require "keg"
 require "cli/parser"
+require "cask/cmd"
+require "cask/caskroom"
 
 module Homebrew
   module_function
@@ -22,43 +24,67 @@ module Homebrew
       flag   "--json",
              description: "Print output in JSON format. Currently the default and only accepted "\
                           "value for <version> is `v1`. See the docs for examples of using the JSON "\
-                          "output: <https://docs.brew.sh/Querying-Brew>"
+                          "output: <https://docs.brew.sh/Querying-Brew>."\
+                          "By default, this option treats all arguments as formulae."\
+                          "To treat arguments as casks, use the --cask-only option."
       switch "--fetch-HEAD",
              description: "Fetch the upstream repository to detect if the HEAD installation of the "\
                           "formula is outdated. Otherwise, the repository's HEAD will only be checked for "\
                           "updates when a new stable or development version has been released."
+      switch "--greedy",
+             description: "Print outdated casks with `auto_updates` or `version :latest`"
+      switch "--formula-only",
+             description: "Treat all arguments as formulae"
+      switch "--cask-only",
+             description: "Treat all arguments as casks"
       switch :debug
       conflicts "--quiet", "--verbose", "--json"
+      conflicts "--formula-only", "--cask-only"
     end
   end
 
   def outdated
     outdated_args.parse
 
-    formulae = if args.resolved_formulae.blank?
-      Formula.installed
+    if args.formula_only? || !args.cask_only? && args.json
+      formulae = args.resolved_formulae.blank? ? Formula.installed : args.resolved_formulae
+      outdated = print_outdated_formulae(formulae)
+
+      Homebrew.failed = !formulae.blank? && !outdated.blank?
+    elsif args.cask_only?
+      casks = args.named.blank? ? Cask::Caskroom.casks : args.named
+      outdated = print_outdated_casks(casks)
+
+      Homebrew.failed = !casks.blank? && !outdated.blank?
     else
-      args.resolved_formulae
+      formulae, casks = args.resolved_formulae_casks
+
+      if formulae.blank? && casks.blank?
+        formulae = Formula.installed
+        casks = Cask::Caskroom.casks
+      end
+
+      outdated_formulae = print_outdated_formulae(formulae)
+      outdated_casks = print_outdated_casks(casks)
+
+      Homebrew.failed = !formulae.blank? && !outdated_formulae.blank? || !casks.blank? && !outdated_casks.blank?
     end
+  end
+
+  def print_outdated_formulae(formulae)
     if args.json
       raise UsageError, "invalid JSON version: #{args.json}" unless ["v1", true].include? args.json
 
-      outdated = print_outdated_json(formulae)
-    else
-      outdated = print_outdated(formulae)
+      return print_outdated_formulae_json(formulae)
     end
-    Homebrew.failed = args.resolved_formulae.present? && !outdated.empty?
-  end
 
-  def print_outdated(formulae)
-    verbose = ($stdout.tty? || args.verbose?) && !args.quiet?
     fetch_head = args.fetch_HEAD?
 
     outdated_formulae = formulae.select { |f| f.outdated?(fetch_head: fetch_head) }
                                 .sort
 
     outdated_formulae.each do |f|
-      if verbose
+      if verbose?
         outdated_kegs = f.outdated_kegs(fetch_head: fetch_head)
 
         current_version = if f.alias_changed?
@@ -87,7 +113,7 @@ module Homebrew
     end
   end
 
-  def print_outdated_json(formulae)
+  def print_outdated_formulae_json(formulae)
     json = []
     fetch_head = args.fetch_HEAD?
     outdated_formulae = formulae.select { |f| f.outdated?(fetch_head: fetch_head) }
@@ -110,4 +136,20 @@ module Homebrew
 
     outdated
   end
+
+  def print_outdated_casks(casks)
+    outdated = casks.map { |cask| Cask::CaskLoader.load(cask) }.select do |cask|
+      odebug "Checking update info of Cask #{cask}"
+      cask.outdated?(args.greedy?)
+    end
+
+    output = outdated.map { |cask| cask.outdated_info(args.greedy?, verbose?, args.json?) }
+    puts args.json ? JSON.generate(output) : output
+
+    outdated
+  end
+
+  def verbose?
+    ($stdout.tty? || args.verbose?) && !args.quiet?
+  end
 end