The 67-year-old actor has found it more difficult with his cognitive abilities, the family writes.
Aphasia is a condition that affects the ability to speak, read and write.
"After careful consideration, he has decided to end his career, which has meant so much to him."
The statement was signed by his current wife Emma Hemming Willis, ex-wife Demi Moore and children Rumer, Scout, Tallulah, Mabel and Evelyn Willis.
"This is a difficult time for us and we are so grateful for your compassion, your love and your support," the family continues.
Bruce Willis is one of the world's most famous actors.
He broke through with the TV series Couples in Crime in the mid-1980s, and became a superstar with the action film Die hard which came out in 1988. The film has had several sequels.
He has also appeared in Armageddon and the Fifth Element, among others.
Bruce Willis is also featured in several films that have not yet premiered, including Paradise City and White Elephant.