diff --git a/plug.vim b/plug.vim
index 8f2680e..0909d28 100644
--- a/plug.vim
+++ b/plug.vim
@@ -438,7 +438,7 @@ function! s:parse_options(arg)
   elseif type == s:TYPE.dict
     call extend(opts, a:arg)
     if has_key(opts, 'tag')
-      let opts.branch = remove(opts, 'tag')
+      let opts.tag = remove(opts, 'tag')
     endif
     if has_key(opts, 'dir')
       let opts.dir = s:dirpath(expand(opts.dir))
@@ -950,13 +950,16 @@ while 1 " Without TCO, Vim stack is bound to explode
   call s:log(new ? '+' : '*', name, pull ? 'Updating ...' : 'Installing ...')
   redraw
 
+  let checkout = s:shellesc(has_key(spec, 'tag') ? spec.tag : spec.branch)
+  let merge = s:shellesc(has_key(spec, 'tag') ? spec.tag : 'origin/'.spec.branch)
+
   if !new
     let [valid, msg] = s:git_valid(spec, 0)
     if valid
       if pull
         call s:spawn(name,
-          \ printf('(git fetch %s 2>&1 && git checkout -q %s 2>&1 && git merge --ff-only origin/%s 2>&1 && git submodule update --init --recursive 2>&1)',
-          \ prog, s:shellesc(spec.branch), s:shellesc(spec.branch)), { 'dir': spec.dir })
+          \ printf('(git fetch %s 2>&1 && git checkout -q %s 2>&1 && git merge --ff-only %s 2>&1 && git submodule update --init --recursive 2>&1)',
+          \ prog, checkout, merge), { 'dir': spec.dir })
       else
         let s:jobs[name] = { 'running': 0, 'result': 'Already installed', 'error': 0 }
       endif
@@ -968,7 +971,7 @@ while 1 " Without TCO, Vim stack is bound to explode
           \ printf('git clone %s --recursive %s -b %s %s 2>&1',
           \ prog,
           \ s:shellesc(spec.uri),
-          \ s:shellesc(spec.branch),
+          \ checkout,
           \ s:shellesc(s:trim(spec.dir))), { 'new': 1 })
   endif
 
@@ -1145,8 +1148,9 @@ function! s:update_ruby()
       threads << Thread.new {
         while pair = take1.call
           name = pair.first
-          dir, uri, branch = pair.last.values_at *%w[dir uri branch]
-          branch = esc branch
+          dir, uri, branch, tag = pair.last.values_at *%w[dir uri branch tag]
+          checkout = esc(tag ? tag : branch)
+          merge = esc(tag ? tag : "origin/#{branch}")
           subm = "git submodule update --init --recursive 2>&1"
           exists = File.directory? dir
           ok, result =
@@ -1167,7 +1171,7 @@ function! s:update_ruby()
               else
                 if pull
                   log.call name, 'Updating ...', :update
-                  bt.call "#{cd} #{dir} && (git fetch #{progress} 2>&1 && git checkout -q #{branch} 2>&1 && git merge --ff-only origin/#{branch} 2>&1 && #{subm})", name, :update, nil
+                  bt.call "#{cd} #{dir} && (git fetch #{progress} 2>&1 && git checkout -q #{checkout} 2>&1 && git merge --ff-only #{merge} 2>&1 && #{subm})", name, :update, nil
                 else
                   [true, skip]
                 end
@@ -1175,7 +1179,7 @@ function! s:update_ruby()
             else
               d = esc dir.sub(%r{[\\/]+$}, '')
               log.call name, 'Installing ...', :install
-              bt.call "git clone #{progress} --recursive #{uri} -b #{branch} #{d} 2>&1", name, :install, proc {
+              bt.call "git clone #{progress} --recursive #{uri} -b #{checkout} #{d} 2>&1", name, :install, proc {
                 FileUtils.rm_rf dir
               }
             end
@@ -1257,13 +1261,19 @@ function! s:git_valid(spec, check_branch)
       let ret = 0
     elseif a:check_branch
       let branch = result[0]
-      if a:spec.branch !=# branch
+      " Check tag
+      if has_key(a:spec, 'tag')
         let tag = s:system_chomp('git describe --exact-match --tags HEAD 2>&1', a:spec.dir)
-        if a:spec.branch !=# tag
-          let msg = printf('Invalid branch/tag: %s (expected: %s). Try PlugUpdate.',
-                \ (empty(tag) ? branch : tag), a:spec.branch)
+        if a:spec.tag !=# tag
+          let msg = printf('Invalid tag: %s (expected: %s). Try PlugUpdate.',
+                \ (empty(tag) ? 'N/A' : tag), a:spec.tag)
           let ret = 0
         endif
+      " Check branch
+      elseif a:spec.branch !=# branch
+        let msg = printf('Invalid branch: %s (expected: %s). Try PlugUpdate.',
+              \ branch, a:spec.branch)
+        let ret = 0
       endif
     endif
   else
diff --git a/test/workflow.vader b/test/workflow.vader
index cd2b09e..21ec7e7 100644
--- a/test/workflow.vader
+++ b/test/workflow.vader
@@ -32,7 +32,7 @@ Execute (Subsequent plug#begin() calls will reuse g:plug_home):
   AssertEqual temp_plugged, g:plug_home
 
 Execute (Test Plug command):
-  " Git repo with branch
+^ Git repo with branch (DEPRECATED. USE BRANCH OPTION)
   Plug 'junegunn/seoul256.vim', 'yes-t_co'
   AssertEqual 'file:///tmp/junegunn/seoul256.vim', g:plugs['seoul256.vim'].uri
   AssertEqual join([temp_plugged, 'seoul256.vim/'], '/'), g:plugs['seoul256.vim'].dir
@@ -41,14 +41,14 @@ Execute (Test Plug command):
   Plug 'junegunn/seoul256.vim', { 'branch': 'no-t_co' } " Using branch option
   AssertEqual 'no-t_co', g:plugs['seoul256.vim'].branch
 
-  " Git repo with tag
+^ Git repo with tag (DEPRECATED. USE TAG OPTION)
   Plug 'junegunn/goyo.vim', '1.5.2'
   AssertEqual 'file:///tmp/junegunn/goyo.vim', g:plugs['goyo.vim'].uri
   AssertEqual join([temp_plugged, 'goyo.vim/'], '/'), g:plugs['goyo.vim'].dir
   AssertEqual '1.5.2', g:plugs['goyo.vim'].branch
 
   Plug 'junegunn/goyo.vim', { 'tag': '1.5.3' } " Using tag option
-  AssertEqual '1.5.3', g:plugs['goyo.vim'].branch
+  AssertEqual '1.5.3', g:plugs['goyo.vim'].tag
 
   " Git URI
   Plug 'file:///tmp/jg/vim-emoji'
@@ -109,7 +109,27 @@ Execute (PlugStatus after installation):
   AssertExpect 'OK', 4
   q
 
+Execute (PlugUpdate - tagged plugin should not fail (#174)):
+  PlugUpdate goyo.vim
+  Log getline(1, '$')
+  AssertExpect '^- goyo.vim', 1
+  q
+
 Execute (Change tag of goyo.vim):
+  call plug#begin()
+  Plug 'junegunn/goyo.vim', { 'tag': '9.9.9' }
+  call plug#end()
+
+Execute (PlugStatus):
+  call PlugStatusSorted()
+
+Expect:
+      Invalid tag: 1.5.3 (expected: 9.9.9). Try PlugUpdate.
+  Finished. 1 error(s).
+  [=]
+  x goyo.vim:
+
+Execute (Remove tag of goyo.vim):
   call plug#begin()
   Plug 'junegunn/goyo.vim'
   call plug#end()
@@ -118,7 +138,7 @@ Execute (PlugStatus):
   call PlugStatusSorted()
 
 Expect:
-      Invalid branch/tag: 1.5.3 (expected: master). Try PlugUpdate.
+      Invalid branch: HEAD (expected: master). Try PlugUpdate.
   Finished. 1 error(s).
   [=]
   x goyo.vim:
@@ -142,12 +162,34 @@ Execute (PlugStatus):
   call PlugStatusSorted()
 
 Expect:
-      Invalid branch/tag: no-t_co (expected: master). Try PlugUpdate.
+      Invalid branch: no-t_co (expected: master). Try PlugUpdate.
   - vim-emoji: OK
   Finished. 1 error(s).
   [==]
   x seoul256.vim:
 
+Execute (PlugUpdate to switch branch, then PlugStatus):
+  PlugUpdate
+  call PlugStatusSorted()
+
+Expect:
+  - seoul256.vim: OK
+  - vim-emoji: OK
+  Finished. 0 error(s).
+  [==]
+
+Execute (Change tag of seoul256.vim):
+  call plug#begin()
+  Plug 'junegunn/seoul256.vim', { 'tag': 'no-such-tag' }
+  call plug#end()
+  call PlugStatusSorted()
+
+Expect:
+      Invalid tag: N/A (expected: no-such-tag). Try PlugUpdate.
+  Finished. 1 error(s).
+  [=]
+  x seoul256.vim:
+
 Execute (Change URI of seoul256.vim):
   call plug#begin()
   Plug 'junegunn.choi/seoul256.vim'