diff --git a/README.md b/README.md
index cd4f43d..1f8e1a1 100644
--- a/README.md
+++ b/README.md
@@ -332,15 +332,16 @@ of the selected items.
 
 `fzf#run()` may take an options-dictionary:
 
-| Option name | Type          | Description                                                         |
-| ----------- | ------------- | ------------------------------------------------------------------- |
-| `source`    | string        | External command to generate input to fzf (e.g. `find .`)           |
-| `source`    | list          | Vim list as input to fzf                                            |
-| `sink`      | string        | Vim command to handle the selected item (e.g. `e`, `tabe`)          |
-| `sink`      | funcref       | Reference to function to process each selected item                 |
-| `options`   | string        | Options to fzf                                                      |
-| `dir`       | string        | Working directory                                                   |
-| `tmux`      | number/string | Use tmux split if possible with the given height (e.g. `20`, `50%`) |
+| Option name   | Type          | Description                                                        |
+| ------------- | ------------- | ------------------------------------------------------------------ |
+| `source`      | string        | External command to generate input to fzf (e.g. `find .`)          |
+| `source`      | list          | Vim list as input to fzf                                           |
+| `sink`        | string        | Vim command to handle the selected item (e.g. `e`, `tabe`)         |
+| `sink`        | funcref       | Reference to function to process each selected item                |
+| `options`     | string        | Options to fzf                                                     |
+| `dir`         | string        | Working directory                                                  |
+| `tmux_width`  | number/string | Use tmux vertical split with the given height (e.g. `20`, `50%`)   |
+| `tmux_height` | number/string | Use tmux horizontal split with the given height (e.g. `20`, `50%`) |
 
 #### Examples
 
@@ -366,9 +367,9 @@ nnoremap <silent> <Leader>C :call fzf#run({
 \   'source':
 \     map(split(globpath(&rtp, "colors/*.vim"), "\n"),
 \         "substitute(fnamemodify(v:val, ':t'), '\\..\\{-}$', '', '')"),
-\   'sink':    'colo',
-\   'options': '+m',
-\   'tmux':    15
+\   'sink':       'colo',
+\   'options':    '+m',
+\   'tmux_width': 20
 \ })<CR>
 ```
 
diff --git a/plugin/fzf.vim b/plugin/fzf.vim
index 0b80931..0020b0b 100644
--- a/plugin/fzf.vim
+++ b/plugin/fzf.vim
@@ -21,6 +21,7 @@
 " OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 " WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+let s:min_tmux_width  = 10
 let s:min_tmux_height = 3
 let s:default_tmux_height = '40%'
 
@@ -88,14 +89,19 @@ function! fzf#run(...) abort
   endif
   let command = prefix.s:exec.' '.optstr.' > '.temps.result
 
-  if s:tmux_enabled() && has_key(dict, 'tmux') &&
-        \ dict.tmux > 0 && winheight(0) >= s:min_tmux_height
+  if s:tmux_enabled() && s:tmux_splittable(dict)
     return s:execute_tmux(dict, command, temps)
   else
     return s:execute(dict, command, temps)
   endif
 endfunction
 
+function! s:tmux_splittable(dict)
+  return
+  \ min([&columns, get(a:dict, 'tmux_width', 0)]) >= s:min_tmux_width ||
+  \ min([&lines, get(a:dict, 'tmux_height', get(a:dict, 'tmux', 0))]) >= s:min_tmux_height
+endfunction
+
 function! s:pushd(dict)
   if has_key(a:dict, 'dir')
     let a:dict.prev_dir = getcwd()
@@ -128,17 +134,25 @@ function! s:execute_tmux(dict, command, temps)
     let command = a:command
   endif
 
-  if type(a:dict.tmux) == 1 && a:dict.tmux =~ '%$'
-    let height = '-p '.a:dict.tmux[0:-2]
+  let splitopt = '-v'
+  if has_key(a:dict, 'tmux_width')
+    let splitopt = '-h'
+    let size = a:dict.tmux_width
   else
-    let height = '-l '.a:dict.tmux
+    let size = get(a:dict, 'tmux_height', get(a:dict, 'tmux'))
+  endif
+
+  if type(size) == 1 && size =~ '%$'
+    let sizeopt = '-p '.size[0:-2]
+  else
+    let sizeopt = '-l '.size
   endif
 
   let s:pane = substitute(
     \ system(
       \ printf(
-        \ 'tmux split-window %s -P -F "#{pane_id}" %s',
-        \ height, s:shellesc(command))), '\n', '', 'g')
+        \ 'tmux split-window %s %s -P -F "#{pane_id}" %s',
+        \ splitopt, sizeopt, s:shellesc(command))), '\n', '', 'g')
   let s:dict = a:dict
   let s:temps = a:temps