The ninth and final season of How I Met Your Mother, an American sitcom created by Carter Bays and Craig Thomas, premiered on CBS on September 23, 2013, with two episodes, and concluded on March 31, 2014. The show was renewed for the final season on December 21, 2012, after cast member Jason Segel changed his decision to leave the show after Season 8. Cristin Milioti, who was revealed as "The Mother" in the Season 8 finale, was promoted to a series regular, the only time How I Met Your Mother added a new regular cast member. Season 9 consists of 24 episodes, each running approximately 22 minutes in length.

Theodore Evelyn Mosby is a fictional character and the protagonist in the American sitcom How I Met Your Mother, portrayed by Josh Radnor. He serves as the show's narrator from the future, voiced by Bob Saget, as he tells his children the "long version" of how he met their mother.