[5] The program draws from "An Unbelievable Story of Rape" (2015), a Pulitzer Prize–winning article by T. Christian Miller and Ken Armstrong for ProPublica and The Marshall Project.

[2] On January 22, 2018, Netflix ordered Unbelievable from Timberman/Beverly Productions and CBS Television Studios with executive producers including Susannah Grant, Michael Chabon, Ayelet Waldman, Sarah Timberman, Carl Beverly, and Katie Couric.

The eight episode miniseries is based on an article by ProPublica and The Marshall Project, "An Unbelievable Story of Rape" written by T. Christian Miller and Ken Armstrong about a case in Lynnwood, Washington.

[15] In August 2018, it was announced that Kai Lennox, Austin Hébert, Dale Dickey, Omar Maskati, Elizabeth Marvel, Liza Lapira, and Eric Lange had been cast in recurring roles.

The website's critical consensus reads, "Heartbreaking and powerful, Unbelievable transcends familiar true-crime beats by shifting its gaze to survivors of abuse, telling their stories with grace and gravity.