Kawai Tsugunosuke (河井 継之助, January 27, 1827 – October 1, 1868) was a Japanese samurai of the late Edo period, who served the Makino clan of Nagaoka. Kawai was a senior military commander of Nagaoka forces during the Boshin War of 1868-1869. He escaped to nearby Aizu after his domain's fall; however, he contracted gangrene from an untreated leg wound, and died in Aizu.