Add this to .vimrc:
```vim
set clipboard=unnamed
```
If you use Tmux you probably need this:
https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard
```bash
$ brew install reattach-to-user-namespace
```
Note, do NOT use something like this because it doesn't work perfectly:
```vim
function! ClipboardYank()
call system('pbcopy', @@)
endfunction
function! ClipboardPaste()
let @@ = system('pbpaste')
endfunction
vnoremap y y:call ClipboardYank()
vnoremap d d:call ClipboardYank()
nnoremap p :call ClipboardPaste()p
```