Tisei said he would make the announcement in a Web video and rally in the state on Thursday, according to the Boston Globe.
Democrats are confident Tierney can fight off another challenge, asserting many of the attacks against him were hashed out in the last cycle and will prove less effective this time around. He has served since 1997.
Tisei will be one of two openly gay Republicans running in a House race nationwide. Recently married, Tisei is also a supporter of abortion rights. If elected, he would be the first Republican from the state to serve in the House since 1994.
According to the Globe, Tisei said he would make fighting against ObamaCare one of the central aspects of his campaign.