Who is Raj's best friend in The Big Bang Theory?

Raj's best friend in The Big Bang Theory is Howard Wolowitz. Their close friendship is one of the show's central relationships, alongside the friendships among Leonard, Sheldon, and Penny.

Rajesh Koothrappali and Howard meet through Caltech's social circle and become especially close because they share a love of science fiction, comics, video games, and elaborate schemes. Howard is often Raj's most frequent companion outside the larger group, and Raj spends significant time with Howard and his family, including Howard's mother and later Bernadette.

Their bond is played for comedy: they tease each other, act like an old married couple, and occasionally argue over loyalty, dating, and personal boundaries. In Season 11, Raj even confronts Howard after feeling that Howard's constant jokes have damaged his confidence, showing that their friendship is important enough to drive a major storyline.

A common mix-up is choosing Leonard or Sheldon, since both are among the show's main friendships. Leonard is Sheldon's closest friend and roommate for much of the series, while Raj's most clearly identified best friend is Howard.