Written by Matt Whiteley, the film chronicles Steve Jobs' (Kutcher) rise from hippie to co-founder of Apple. Gad would play Wozniak, who created the Apple I computer and co-created the Apple II computer in the mid-1970s.
Mark Hulme will produce the film, which is scheduled to begin production in May.
Gad currently stars as Elder Cunningham in The Book of Mormon, a role that earned him a 2011 Tony Award nomination. He has also been seen on Broadway in The 25th Annual Putnam County Spelling Bee and is known for his television work, which includes "The Daily Show" and "Back to You," among others. As previously reported, he will co-write, executive produce and star in NBC's "1600 Penn."