What is the name of Barney Stinson's maternal half-brother?

Barney Stinson's maternal half-brother is James Stinson.

James and Barney share their mother, Loretta Stinson, but have different biological fathers. James is played by Wayne Brady and is introduced as Barney's older half-brother. The two resemble each other in their confidence, taste for suits, and skill at acting as each other's “wingmen,” although James's life develops in a very different direction.

James is gay and later marries Tom, his longtime partner. Together, James and Tom adopt two children, Eli and Sadie. Their relationship becomes part of the show's broader exploration of family, commitment, and Barney's difficulty accepting changes in the people closest to him.

James's biological father is Sam Gibbs, a fact revealed in the season-six episode “Cleaning House.” This is easy to mix up with Barney's paternal half-siblings, Jerome Jr. and Carly Whittaker, who are connected to Barney through his biological father Jerome. James is specifically Barney's maternal half-brother because both men are Loretta's sons.