What is the difference between a gross lease and a net lease?

A gross lease requires the tenant to pay a fixed rent amount while the landlord pays all operating expenses including property taxes, insurance, and maintenance. A net lease requires the tenant to pay base rent plus some or all operating expenses. A single net lease adds property taxes, a double net adds taxes and insurance, and a triple net or NNN lease adds taxes, insurance, and maintenance, making the tenant responsible for nearly all property costs.