Hōzōin-ryū (宝蔵院流) is a traditional school (koryū) of Japanese martial arts that specializes in the art of spearmanship (sōjutsu). Hōzōin-ryū was founded by Hōzōin Kakuzenbō In'ei in c. 1560. In'ei was a Buddhist monk of Kōfuku-ji Temple in Nara, Japan. He adored martial arts and trained in the art of swordsmanship. At the same time, he was coached and mentored by Daizendayū Moritada (大膳太夫盛忠), a master of the spear. Under this master's guidance, In'ei honed his spearmanship.

Hōzōin Kakuzenbō In'ei was a Buddhist monk and sōhei, abbot of Hōzōin temple, and guardian of all the temples of Nara. In the 1560's he founded Hōzōin-ryū, a school which taught the art of the spear, also known as Sōjutsu.