The fourth season of the American television comedy series How I Met Your Mother premiered on September 22, 2008 and concluded on May 18, 2009.

CBS broadcast the fourth season on Monday nights at 8:30 pm in the United States.

The complete fourth season was released on Region 1 DVD on September 29, 2009.

Michelle stated, "This fourth season seemed to settle down the chase for the titular mother.

With Robin homesick and unemployed (and at risk of being deported), this pairing brought out the best Robin Sparkles reference of the season, when Marshall leads a rousing karaoke version of "Let's Go to the Mall!