The organization reports that 4.4% of the regulars - 31 out of a total of 701 characters - will be gay in the 97 scripted series airing on the major broadcast networks.
The proportion is up from 2.9% last year and 3.9% in the 2010-11 season.
ABC leads with ten characters out of 194, followed by Fox with six out of 118.
"More and more Americans have come to accept their LGBT family members, friends, co-workers, and peers, and as audiences tune into their favorite programs, they expect to see the same diversity of people they encounter in their daily lives," said GLAAD President Herndon Graddick in a statement.
Last year saw a decrease in the percentage of gay characters.
Scripted cable network shows have also seen an increase, with 35 regular gay characters up from last year's 29.