Nagao Masakage (長尾 政景?, 1526 – August 11, 1564) was the head of the Ueda Nagao clan following the Sengoku period of the 16th century of Japan. Masakage was the brother-in-law of the famous Uesugi Kenshin, the "Dragon of Echigo". Masakage was the father of Uesugi Kagekatsu.
Even though Masakage may have been the brother-in-law of Kenshin, he still supported Nagao Harukage in a fight against Kenshin. Masakage later on became a retainer under Kenshin, but it is not known if he truly was assassinated on Kenshin's orders.