Stroke on what side of the brain would experience a left facial droop?

Stroke: Right cerebrum. But facial droop can also be from bell's palsy. A neurologist can sort that out.

Stroke vrs Bell's : The picture shows a lady with a stroke and a man with bell's palsy: if you can raise both eyebrows, the facial nerve is intact. Therefore, the woman has had a stroke involving the left side of the brain producing paralysis of the right lower face and the man has a right bell's palsy.

It Depends: The short answer is the right if you're referring to the most common cause of stroke (a cortical stroke), but the wiring from the cortex to the face does a little zig zag in there, so the most specific answer depends on the level of the brain where the stroke occurred.