John "Johnny" Jahr (born 10 April 1965 in Hamburg) is a retired German curler.

Germany's poor performances in recent World Championships failed to automatically qualify the nation for the 2014 Winter Olympics.

Jahr also played at the 2014 World Men's Curling Championship, where Germany finished in eighth place with a 5–6 win–loss record.

Jahr announced his retirement from international curling at the conclusion of the round robin at the World Championship.

Jahr also owns a real estate company and is a shareholder in multiple casinos.