Sometimes - however you'll want to check for this specific language in your loan documents. You typically don't see them as often anymore from my understanding. I haven't come across very many personally. Typically, if there is a penalty for paying the amount financed off early, it is only applicable for a certain period of time within the life of the loan.
Why "would" there be a penalty? Because in a perfect world, the lender wants to keep the amount financed outstanding for the life of the loan. You pay the the most interest that way, and they in turn make the most money.
I'm not in the business of giving financial advice, so this is just my personal opinion. Even if you have the money to do so, you'll want to weigh the benefits of paying off your mortgage carefully. You might be better served investing that money elsewhere, if your interest rate is super low - especially since the interest is tax deductible.
Talk to your financial professional and make sure you crunch the numbers to see if your plan makes financial sense.
Hope that helps!