The Duke of Cambridge was named "straight ally of the year" at the British LGBT Awards on Friday evening, the BBC reported.
"It's so important to be proud of the person you are" he said via a video message.
Prince William, who appeared on the cover of gay magazine Attitude last year, made the video message ahead of the ceremony in London's Grand Connaught Rooms.
In the video, he said: "In recent years I've become passionate about what we can do to protect people from bullying, particularly online.
"It is 2017, and nobody should be bullied for their sexuality, or for any other reason," the BBC quoted the Duke as saying.
The awards, in their sixth year, recognise individuals and organisations which promote equality for LGBT people.