Ōmura Yoshiaki (大村 喜前, 1568 – September 18, 1615) was a ruling head of the clan of Omura throughout the latter Sengoku Period of Feudal Japan. As Yoshiaki was the respective son of Omura Sumitada, he followed his father in succession at some variable time, at which relations with the Jesuits and trade with the Portuguese had been already firmly developed. Following Ryuzoji Takanobu's suppression of the Omura in the year of 1580, it can be surmised that Yoshiaki then followed with support beneath the former, at which he would rettain the lowly position of vassal up until the Toyotomi's rise to prominence after 1584. Supporting Toyotomi Hideyoshi initially during the Korean Campaign of 1592, Yoshiaki's mutual support following this scenario is relatively unknown, but it is recorded that he at least chose to remain as a neutral power by the year of 1600, where he declined the proposal to attend the Sekigahara Campaign. As Yoshiaki was subsequently forced to stand down in favor of his son, Sumitada, by the irrational consequence of not supporting the Tokugawa's Western army in Sekigahara, Yoshiaki still entered the Edo Period with a level of authority over the Omura, which he justified by means of expelling the Jesuits from his domain after a defiant show of disposition within the Nagasaki port. Initially following this choice of action, Yoshiaki forced Christianity from his clan and rationally enforced Buddhism, most surmisabely to be seen in a good light to Tokugawa Ieyasu and potentially receive redeemed rank that could benefit his social position. As his Christian name 'Dom Sancho' was additionally discarded within such an event, Yoshiaki's life following this period in time is unknown, but he regardlessly died by the year of 1615.
Yoshiaki was the son of Ōmura Sumitada.