If you are on an L1 visa do you have to file an federal income tax return?

I moved this to Taxes where our Tax Experts can see it better.

Depends!

If you are on L-1 visa, get paid in your home country courrency from your home country office, and are in the U.S. for less than 183 days, then it is likely your slary is tax exempt and no tax return is due.

However, exceed 183 days or get paid from U.S.-based office, and you become liable for U.S. income taxes.