diff --git a/completions/bash/brew b/completions/bash/brew
index 967363f593..035782f253 100644
--- a/completions/bash/brew
+++ b/completions/bash/brew
@@ -2028,6 +2028,24 @@ _brew_ruby() {
   __brew_complete_files
 }
 
+_brew_rubydoc() {
+  local cur="${COMP_WORDS[COMP_CWORD]}"
+  case "${cur}" in
+    -*)
+      __brewcomp "
+      --debug
+      --help
+      --only-public
+      --open
+      --quiet
+      --verbose
+      "
+      return
+      ;;
+    *) ;;
+  esac
+}
+
 _brew_search() {
   local cur="${COMP_WORDS[COMP_CWORD]}"
   case "${cur}" in
@@ -2759,6 +2777,7 @@ _brew() {
     remove) _brew_remove ;;
     rm) _brew_rm ;;
     ruby) _brew_ruby ;;
+    rubydoc) _brew_rubydoc ;;
     search) _brew_search ;;
     sh) _brew_sh ;;
     style) _brew_style ;;
diff --git a/completions/fish/brew.fish b/completions/fish/brew.fish
index e8ab276a78..cfd60856b8 100644
--- a/completions/fish/brew.fish
+++ b/completions/fish/brew.fish
@@ -1363,6 +1363,15 @@ __fish_brew_complete_arg 'ruby' -l e -d 'Execute the given text string as a scri
 __fish_brew_complete_arg 'ruby' -l r -d 'Load a library using `require`'
 
 
+__fish_brew_complete_cmd 'rubydoc' 'Generate Homebrew\'s RubyDoc documentation'
+__fish_brew_complete_arg 'rubydoc' -l debug -d 'Display any debugging information'
+__fish_brew_complete_arg 'rubydoc' -l help -d 'Show this message'
+__fish_brew_complete_arg 'rubydoc' -l only-public -d 'Only generate public API documentation'
+__fish_brew_complete_arg 'rubydoc' -l open -d 'Open generated documentation in a browser'
+__fish_brew_complete_arg 'rubydoc' -l quiet -d 'Make some output more quiet'
+__fish_brew_complete_arg 'rubydoc' -l verbose -d 'Make some output more verbose'
+
+
 __fish_brew_complete_cmd 'search' 'Perform a substring search of cask tokens and formula names for text'
 __fish_brew_complete_arg 'search' -l archlinux -d 'Search for text in the given database'
 __fish_brew_complete_arg 'search' -l cask -d 'Search for casks'
diff --git a/completions/internal_commands_list.txt b/completions/internal_commands_list.txt
index 45d6e2f367..b9ae55c71e 100644
--- a/completions/internal_commands_list.txt
+++ b/completions/internal_commands_list.txt
@@ -85,6 +85,7 @@ remove
 rm
 rubocop
 ruby
+rubydoc
 search
 setup-ruby
 sh
diff --git a/completions/zsh/_brew b/completions/zsh/_brew
index 1253d2becb..6a4fe95e06 100644
--- a/completions/zsh/_brew
+++ b/completions/zsh/_brew
@@ -205,6 +205,7 @@ __brew_internal_commands() {
     'release:Create a new draft Homebrew/brew release with the appropriate version number and release notes'
     'rubocop:Installs, configures and runs Homebrew'\''s `rubocop`'
     'ruby:Run a Ruby instance with Homebrew'\''s libraries loaded'
+    'rubydoc:Generate Homebrew'\''s RubyDoc documentation'
     'search:Perform a substring search of cask tokens and formula names for text'
     'setup-ruby:Installs and configures Homebrew'\''s Ruby'
     'sh:Enter an interactive shell for Homebrew'\''s build environment'
@@ -1684,6 +1685,17 @@ _brew_ruby() {
     '*::file:__brew_formulae_or_ruby_files'
 }
 
+# brew rubydoc
+_brew_rubydoc() {
+  _arguments \
+    '--debug[Display any debugging information]' \
+    '--help[Show this message]' \
+    '--only-public[Only generate public API documentation]' \
+    '--open[Open generated documentation in a browser]' \
+    '--quiet[Make some output more quiet]' \
+    '--verbose[Make some output more verbose]'
+}
+
 # brew search
 _brew_search() {
   _arguments \
diff --git a/docs/Manpage.md b/docs/Manpage.md
index fbce73728d..c39a488633 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -2554,6 +2554,18 @@ Run e.g. `brew ruby -- --version` to pass arbitrary arguments to `ruby`.
 
 : Execute the given text string as a script.
 
+### `rubydoc` \[`--only-public`\] \[`--open`\]
+
+Generate Homebrew's RubyDoc documentation.
+
+`--only-public`
+
+: Only generate public API documentation.
+
+`--open`
+
+: Open generated documentation in a browser.
+
 ### `sh` \[`--env=`\] \[`--cmd=`\] \[*`file`*\]
 
 Enter an interactive shell for Homebrew's build environment. Use
diff --git a/manpages/brew.1 b/manpages/brew.1
index f3f73d9497..5aa403933a 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -1627,6 +1627,14 @@ Load a library using \fBrequire\fP\&\.
 .TP
 \fB\-e\fP
 Execute the given text string as a script\.
+.SS "\fBrubydoc\fP \fR[\fB\-\-only\-public\fP] \fR[\fB\-\-open\fP]"
+Generate Homebrew\[u2019]s RubyDoc documentation\.
+.TP
+\fB\-\-only\-public\fP
+Only generate public API documentation\.
+.TP
+\fB\-\-open\fP
+Open generated documentation in a browser\.
 .SS "\fBsh\fP \fR[\fB\-\-env=\fP] \fR[\fB\-\-cmd=\fP] \fR[\fIfile\fP]"
 Enter an interactive shell for Homebrew\[u2019]s build environment\. Use years\-battle\-hardened build logic to help your \fB\&\./configure && make && make install\fP and even your \fBgem install\fP succeed\. Especially handy if you run Homebrew in an Xcode\-only configuration since it adds tools like \fBmake\fP to your \fBPATH\fP which build systems would not find otherwise\.
 .TP