A second mortgage is a loan that allows you to borrow against the equity in your home without having to refinance your first mortgage. It’s called a “second” mortgage because it’s secondary to your first mortgage in terms of priority. A second mortgage might be a good idea if you need a large sum of money for things like home improvements, debt consolidation, or major expenses like education or medical bills. Sometimes people choose to take a second mortgage when penalties to break the first mortgage and access equity are too high.