Once Upon a Time features a significant LGBTQ+ storyline with Ruby and Dorothy Gale, whose 'true love' is depicted positively and with dignity. Their relationship is presented as powerful and valid, overcoming external obstacles through an affirming narrative that integrates their queer identity seamlessly into the show's themes.

The series features characters from Arthurian legend, including Merlin, Lancelot, and Guinevere, who are widely established as white in traditional portrayals and source material. These characters are depicted by Black actors in the show, constituting clear instances of race swapping.