One 31, fully known as Channel One 31 (Thai: สถานีโทรทัศน์ช่องวัน 31) and branded as One31 or One HD 31, is a Thai digital terrestrial television channel owned by GMM Grammy under The One Enterprise.

The network offers a variety of content such as drama, variety programs, competition, news and entertainment programs.

[1][2] One 31 first aired on December 1, 2011 with the name 1-Sky One (วัน-สกาย วัน) with content and television programs produced by companies under GMM Grammy.

On April 1, 2012, it changed its name into GMM Z Hitz (จีเอ็มเอ็มแซต ฮิตส์).

On November 1, 2012, the channel changed its name to GMM One.