155th Regiment may refer to:
155th Artillery Regiment "Emilia" 155th Infantry Regiment (United States) 155th (Mixed) Heavy Anti-Aircraft Regiment, Royal Artillery 155th (Wessex) Transport Regiment, a unit of the United Kingdom Territorial Army
American Civil War regiments 155th Illinois Infantry Regiment 155th Indiana Infantry Regiment 155th New York Infantry Regiment 155th Ohio Infantry Regiment 155th Pennsylvania Infantry Regiment
See also 155th Division (disambiguation)