A lubrication system (100) for a gas turbine engine (10) includes a tank (114), a circulation pump, and a heat exchanger (152). The circulation pump generates a flow of lubricant from the tank (114) to, e.g., a power gear box (46) of the gas turbine engine (10) and the heat exchanger (152) removes an amount of heat from such flow of lubricant provided to the power gear box (46). The lubrication system (100) also includes one or more valves in the flow of lubricant for controlling a flowrate and/or temperature of the lubricant provided to, e.g., the power gear box (46) to increase an efficiency and/or durability of the power gear box (46).