Meetup is an American social media platform and social networking service for hosting and organizing in-person and virtual activities, gatherings, and events for people and communities of similar interests, hobbies, and professions. The service has 60 million users. The company has both free tiers and paid tiers.

Headquartered in New York City, the company was founded in 2002 by Scott Heiferman and four others. It was acquired by WeWork in November 2017, AlleyCorp in March 2020, and Bending Spoons in January 2024.

Meetup was founded in June 2002 by Scott Heiferman and four co-founders. The idea for Meetup came from Heiferman meeting his neighbors in New York City for the first time after the September 11 attacks. Heiferman was also influenced by the book Bowling Alone, which is about the deterioration of community in American culture. Some initial funding for the venture was raised from friends and family, which was followed by a funding round with angel investors.

The early version of Meetup generated revenues by charging a fee to venues in exchange for bringing Meetup users to their business. Once enough users added themselves to a group, Meetup sent the group members an email, asking them to vote on one of three sponsoring venues for the group to meet.

In 2003, Meetup won the "Community Websites and Mobile Site" Webby Award.

Meetup was originally intended to focus on hobbies and interests, but it was popularized by Presidential hopeful Howard Dean in 2004. Meetup developed paid services to help the Dean campaign to meet with Meetup users. Dean also publicized Meetup groups of supporters in his speeches and on his website; at the peak of Dean's campaign, 143,000 users had joined Meetup groups for Dean supporters.

In early 2005, Meetup began to charge a fee for group organizers. Initially, changes to the website had to be approved by two committees.

In 2008, Union Square Ventures invested in the company.