On "Friends," Chandler shared a college room with Ross Geller.
Ross and Chandler met during their freshman year at college and became close friends before the events of the series. Their college history is mentioned through flashbacks and later conversations, helping explain why Chandler is already part of the Geller family’s orbit when the show begins.
Chandler later moved to New York and became roommates with Joey Tribbiani, while Ross remained his longtime friend. This can cause confusion because Joey is Chandler’s best-known roommate during the main storyline, but Ross was the person who shared his room in college.
Their friendship also connects Chandler to Monica and the wider group: Ross is Monica’s brother, and Chandler eventually marries Monica. The college-roommate detail is therefore an important piece of the group’s backstory, even though viewers mostly see Chandler and Joey living together.