The gay drama about the friendship of two teenage boys is directed by up-and-coming filmmaker Chukiat Sakweerakul who was on hand to receive the awards along with producer Prachya Pinkaew.
Muay Thai Chaiya, Kongkait Komesiri's solo directorial debut about the underground kick-boxing world, bagged the most with five awards. These included best actor for Akara 'Golf' Amarttayakul, best supporting actor for Sonthaya Chitmanee, best art direction, best make-up and best editing.
Bangkok Love Story, a crime thriller with homosexual themes, won three awards for best screenplay, best cinematography and best sound.
With the above three films dominating the awards, best actress went to Marsha Wattanapanich for horror flick Alone.
Last year saw the release of 47 local films, which were all eligible nominees, but Prince Chatrichalerm Yukol chose not to have his mega hits King Naresuan Part 1 and 2 participate in the race.
The awards are given out annually by the Federation of National Film Associations of Thailand.
This year, the red-carpet award ceremony was held on Sunday night (Feb 17) in Bangkok's Siam Niramitr Theatre with about 1,000 guests in attendance.
FULL WINNERS LIST
Best Picture - The Love of Siam
Best Director - Chukiat Sakweerakul (The Love of Siam)
Best Actor - Akara 'Golf' Amarttayakul (Muay Thai Chaiya)
Best Actress - Marsha Wattanapanich (Alone)
Best Supporting Actor - Sonthaya Chitmanee (Muay Thai Chaiya)
Best Supporting Actress - Chermarn Boonyasak (The Love of Siam)
Best Screenplay - Poj Arnon (Bangkok Love Story)
Best Cinematography - Tiwa Moeithaisong (Bangkok Love Story)
Best Editing - Sonit Atwinigon (Muay Thai Chaiya)
Best Art Direction - Tana Maykaampoot and Natniti Sotganwijit (Muay Thai Chaiya)
Best Costume Design - Charaa Wanaalai (Kung Fu Tootsie)
Best Make-Up - Marit Choakbecha (Muay Thai Chaiya)
Best Visual Effects - Julien Vanhoenacker and Joaquim Montserrat (Body #19)
Best Sound - Wachai Rawongsarut (Bangkok Love Story)
Best Original Song - Parinippan (The Life of Buddha)
Best Original Score - Gaywan Golawanotai (The Life of Buddha)