Ijuin Takaaki (died June 1865) was an admiral of the Choshu Domain who commanded the domain's fleet during the Boshin War. His fleet supported the domain's armies during their eastward advance across Honshu, bombarding Yamaguchi in 1864, shelling Bingo Province's harbor during Choshu's war with the Fukuyama Domain, and fighting for control of the Seto Inland Sea at the Battle of Kasaoka and the Battle of Umegato. In May-June 1865, he transported Mori Takachika's army from Bizen Province to Harima Province, but his lone ship was sunk by Sanada Nobuhiro off the coast of Harima shortly after Takachika's army disembarked, killing Takaaki.