Joseph Emilio "Jun" Aguinaldo Abaya (born May 28, 1966) is a Filipino politician, lawyer, and military officer.
He was the Secretary of the Department of Transportation and Communications (DOTC) of the Philippines under the administration of President Benigno Aquino III.
A member of the Liberal Party, he has been elected to three terms as a member of the Philippine House of Representatives, representing the 1st District of Cavite.
He first won election to the House in 2004, and was re-elected in 2007.
He and other Aquino administration officials have been charged over the alleged anomalous contracts for the Metro Rail Transit Line 3 (MRT3) during their time.