Most guest stars featured in a TV series
The Simpsons
United States

With its 26th season airing in 2014–15, the longest-running sitcom, The Simpsons (Fox, USA), has featured more celebrity guests than any other television series to date, with 688 cameos, as of 16 July 2015. Several guests have made repeat appearances in the series, but only the debut cameo is included here, i.e., each guest is only counted once.