Taira no Sadayoshi (平 貞能) was a governor of Higo and Chikugo provinces in Kyūshū, and a samurai commander for the Taira clan during the Genpei War of the 1180s.
Following the war, his life was spared as a result of an intercession by Utsunomiya Tomotsuna.
When Kikuchi Takanao sided with Minamoto no Yoritomo and began levying troops in Kyūshū in 1180, at the beginning of the Genpei War, Sadayoshi marched against him and defeated him.
Sadayoshi then traveled to Kyoto, and met up with Taira no Munemori along with the Emperor Antoku on the Saikaidō road from the capital.
He tried in vain to convince Munemori to return to the city, but ultimately left him to take care of the remains of Taira no Shigemori, which were brought to the sacred Mount Kōya.