According to Official Guinness Records,
The largest game of follow the leader numbers 768 participants, achieved by Dimension Data & Playworks (both USA) in Salt Lake City, Utah, USA, on 10 November 2015. Participants included 4th and 5th grade "junior coaches" from Playworks, who received a Chromebook at the conclusion of the attempt.
For a complete list of 2015 records, please visit 2015 Guinness Records in United States.