diff --git a/Library/Homebrew/cmd/readall.rb b/Library/Homebrew/cmd/readall.rb
index 410ce894bd..2eedf9cb59 100644
--- a/Library/Homebrew/cmd/readall.rb
+++ b/Library/Homebrew/cmd/readall.rb
@@ -11,10 +11,10 @@ module Homebrew
       usage_banner <<~EOS
         `readall` [<options>] [<tap>]
 
-        Import all formulae from the specified <tap>, or from all installed taps if none is provided.
-        This can be useful for debugging issues across all formulae when making
+        Import all items from the specified <tap>, or from all installed taps if none is provided.
+        This can be useful for debugging issues across all items when making
         significant changes to `formula.rb`, testing the performance of loading
-        all formulae or checking if any current formulae have Ruby issues.
+        all items or checking if any current formulae/casks have Ruby issues.
       EOS
       switch "--aliases",
              description: "Verify any alias symlinks in each tap."
@@ -30,7 +30,7 @@ module Homebrew
 
     if args.syntax?
       scan_files = "#{HOMEBREW_LIBRARY_PATH}/**/*.rb"
-      ruby_files = Dir.glob(scan_files).reject { |file| file =~ %r{/(vendor|cask)/} }
+      ruby_files = Dir.glob(scan_files).reject { |file| file =~ %r{/(vendor)/} }
 
       Homebrew.failed = true unless Readall.valid_ruby_syntax?(ruby_files)
     end
diff --git a/Library/Homebrew/extend/os/linux/readall.rb b/Library/Homebrew/extend/os/linux/readall.rb
new file mode 100644
index 0000000000..e9278821e0
--- /dev/null
+++ b/Library/Homebrew/extend/os/linux/readall.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Readall
+  class << self
+    def valid_casks?(*)
+      true
+    end
+  end
+end
diff --git a/Library/Homebrew/extend/os/readall.rb b/Library/Homebrew/extend/os/readall.rb
new file mode 100644
index 0000000000..6ddbc3e6d7
--- /dev/null
+++ b/Library/Homebrew/extend/os/readall.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require "extend/os/linux/readall" if OS.linux?
diff --git a/Library/Homebrew/readall.rb b/Library/Homebrew/readall.rb
index 54c74c01aa..491c406cbb 100644
--- a/Library/Homebrew/readall.rb
+++ b/Library/Homebrew/readall.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "formula"
+require "cask/cask_loader"
 
 module Readall
   class << self
@@ -35,28 +36,43 @@ module Readall
     end
 
     def valid_formulae?(formulae)
-      failed = false
+      success = true
       formulae.each do |file|
         Formulary.factory(file)
       rescue Interrupt
         raise
       rescue Exception => e # rubocop:disable Lint/RescueException
         onoe "Invalid formula: #{file}"
-        puts e
-        failed = true
+        $stderr.puts e
+        success = false
       end
-      !failed
+      success
+    end
+
+    def valid_casks?(casks)
+      success = true
+      casks.each do |file|
+        Cask::CaskLoader.load(file)
+      rescue Interrupt
+        raise
+      rescue Exception => e # rubocop:disable Lint/RescueException
+        onoe "Invalid cask: #{file}"
+        $stderr.puts e
+        success = false
+      end
+      success
     end
 
     def valid_tap?(tap, options = {})
-      failed = false
+      success = true
       if options[:aliases]
         valid_aliases = valid_aliases?(tap.alias_dir, tap.formula_dir)
-        failed = true unless valid_aliases
+        success = false unless valid_aliases
       end
       valid_formulae = valid_formulae?(tap.formula_files)
-      failed = true unless valid_formulae
-      !failed
+      valid_casks = valid_casks?(tap.cask_files)
+      success = false if !valid_formulae || !valid_casks
+      success
     end
 
     private
@@ -79,3 +95,5 @@ module Readall
     end
   end
 end
+
+require "extend/os/readall"
diff --git a/docs/Manpage.md b/docs/Manpage.md
index 0b746685a1..e242f36fc7 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -367,10 +367,10 @@ Rerun the post-install steps for *`formula`*.
 
 ### `readall` [*`options`*] [*`tap`*]
 
-Import all formulae from the specified *`tap`*, or from all installed taps if none
-is provided. This can be useful for debugging issues across all formulae when
-making significant changes to `formula.rb`, testing the performance of loading
-all formulae or checking if any current formulae have Ruby issues.
+Import all items from the specified *`tap`*, or from all installed taps if none is
+provided. This can be useful for debugging issues across all items when making
+significant changes to `formula.rb`, testing the performance of loading all
+items or checking if any current formulae/casks have Ruby issues.
 
 * `--aliases`:
   Verify any alias symlinks in each tap.
diff --git a/manpages/brew.1 b/manpages/brew.1
index 49bf5bd86e..768ffb6b4d 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -482,7 +482,7 @@ Pin the specified \fIformula\fR, preventing them from being upgraded when issuin
 Rerun the post\-install steps for \fIformula\fR\.
 .
 .SS "\fBreadall\fR [\fIoptions\fR] [\fItap\fR]"
-Import all formulae from the specified \fItap\fR, or from all installed taps if none is provided\. This can be useful for debugging issues across all formulae when making significant changes to \fBformula\.rb\fR, testing the performance of loading all formulae or checking if any current formulae have Ruby issues\.
+Import all items from the specified \fItap\fR, or from all installed taps if none is provided\. This can be useful for debugging issues across all items when making significant changes to \fBformula\.rb\fR, testing the performance of loading all items or checking if any current formulae/casks have Ruby issues\.
 .
 .TP
 \fB\-\-aliases\fR