Swee'Pea is a character in E.C. Segar's comic strip Thimble Theatre and in the "Popeye" cartoon series derived from it. His name suggests the flower known as the Sweet Pea. Before the baby came along in the movies, the name "Sweet Pea" was a term of affection used by Popeye. In the cartoon We Aim to Please, at one point he addressed Olive Oyl that way.

In the comics, Swee'Pea is a baby found on Popeye's doorstep, circa 1933. Popeye adopts and raises him as his son, or, as he puts it "boy-kid". Initially Swee'Pea's speech consisted entirely of the sound "glop". As the years went on, Swee'Pea apparently aged enough to speak normally, and could throw punches if he had to; however, his appearance remained that of a crawling baby.

In the animated "Popeye" cartoons produced by Max Fleischer and later by Famous Studios, Swee'Pea was portrayed as being in the care of Olive Oyl, although it was unclear whether he was her own child. In the feature film version, Swee'pea is found on the doorstep of the Oyl home where Popeye lives as a boarder. (In other accounts Swee'pea is depicted as royalty. After Swee'pea's birth father is killed, Swee'pea was made the Crown Prince of Demonia. As he was of royal birth, he needed protection from an evil uncle who wanted to eliminate him and take control of the country. Swee'pea's mother left him on the doorstep of the Oyl home knowing the trustworthy sailor would protect him.) Popeye proposes the name Swee'pea for the child; Olive objects, saying it sounds ridiculous, and he retorts "Well, what were you going to call him? Baby Oyl?" Alice the Goon, originally depicted as a slave of the Sea Hag, reappeared in a flower dress and hat and officially became Swee'pea's babysitter after protests by parents who said the hairy monster frightened children.