Katō Yoshiaki (加藤 嘉明, 1563 – October 7, 1631) was a Japanese daimyō of the late Sengoku period to early Edo period who served as lord of the Aizu Domain. A retainer of Toyotomi Hideyoshi, he fought in the battle of Shizugatake in 1583, and soon became known as one of the shichi-hon-yari (七本槍), or Seven Spears of Shizugatake, Hideyoshi's seven most trusted and experienced generals.
After Hideyoshi's death, Katō fought alongside Tokugawa Ieyasu. Following the important victory at Sekigahara, Tokugawa doubled Katō's fief from 100,000 koku to 200,000. For a time, he was lord of Aizu.
He was involved in the bitter naval battles fought off the coast of southern Korea during the 1st and 2nd Korean Campaign, many of which went in favor of the Korean navy.
- Portrayed by Kim Kang-il in the 2014 film The Admiral: Roaring Currents.
- Turnbull, Stephen (1998). The Samurai Sourcebook. London: Cassell & Co.