Natalia Dyer was only 16 years old when she filmed I Believe in Unicorns (2014), but was 19 by the time the film was first shown at a film festival.
Though they did not share any scenes together, both Natalia Dyer and Amy Seimetz played roles in the hit Netflix show Stranger Things; as Nancy Wheeler (Dyer) and Becky Ives (Seimetz)
According to Leah Meyerhoff, the live action scenes were shot in three weeks in the San Francisco Bay Area.
According to Leah Meyerhoff, the budget for the animated scenes in the film was under $5,000.
According to Leah Meyerhoff, Peter Vack researched his role by hanging out with local punk kids in the Berkeley area.