The story will follow the adventures of a young girl and her pocket-sized pal.
"I'm so thrilled to bring to bear both my love of this historic property and also my deep-seated belief that young women need smart playful films that speak to them without condescension," said the "Girls" creator in a statement.
"Polly Pocket was responsible for countless hours of childhood escapism for me - Polly gave me a tiny world of magic and autonomy to narrate, so it's pretty poetic to be tackling these same ideas now as a director collaborating with the brilliant Lily Collins, Robbie Brenner, Mattel and MGM," she additionally stated.
Collins added, "As a child who was obsessed with Polly Pocket, this is a real dream come true and I can't wait to bring these tiny toys to the big screen."
"Polly Pocket" is currently a Canadian-American animated television series that has aired on the Family Channel and Netflix. It features a young girl called Polly who has a magical locket that allows her and her friends to shrink at will.
It's the latest directorial project for Dunham. She is currently working on the upcoming adaptation of the 1994 young adult novel "Catherine, Called Birdy", and recently completed the comedy "Sharp Stick".