"Angie Baby" is a popular song that was a number-one U.S. hit for Australian singer Helen Reddy. It hit #1 on the Billboard Hot 100 chart at the end of December of 1974 and became one of Reddy's biggest-selling singles. The song also topped the U.S. adult contemporary chart, the singer's fifth #1 on this chart.

The song's cryptic lyrics have inspired a number of listener theories as to what the song is really about, and Reddy has refused to comment on what the true storyline of the song is, partly because she has said she enjoys hearing other listeners' interpretations. Reddy has also said that "Angie Baby" was the one song she never had to push radio stations into playing.

Singer/songwriter Alan O'Day finally revealed in 1998 that the "crazy" heroine in the song had "magic power" and "special abilities", and that he had deliberately blurred the lines between fantasy and reality. However, he still declined to give a detailed explanation of what happened to the boy in the song. Reddy herself had joked that the boy had become "a sound wave", an explanation that O'Day later refuted.

In an article he wrote in 2006, O'Day said the song took three months to write. Originally it was loosely based on the character in the Beatles’ "Lady Madonna". In order to make the character more interesting, he decided to make her abnormal, and he thought of a young next door neighbor girl he had known who had seemed "socially retarded." O'Day said he also thought to his own childhood, since as an only child who was often ill, many of his days were spent in bed with a radio to keep him company. He named the character Angie, probably inspired by the Rolling Stones' song "Angie". Originally the character was just supposed to be mentally "slow," but while writing the song, O'Day showed it to his therapist, who pointed out that the character's reactions in the song were not those of a retarded person, so O'Day changed the lyric from "slow" to "touched," and the character switched from retarded to "crazy." This expanded to her living in a dream world of lovers, inspired by the songs on her radio. When a "neighbor boy with evil on his mind" tries to enter her room to take advantage of the girl, he is instead drawn into her reality, with weird and unexpected consequences. The intent was to show that the Angie character had more power than he or the listener expected; she literally shrank him down into her radio, where he remained as her slave whenever she desired him to come out.

Not everyone understood the meaning of O'Day's lyrics, and when the song was released, it inspired a great deal of speculation as to its true meaning. The song was compared to Bobbie Gentry’s "Ode To Billie Joe" (which had a mystery about "something" thrown off the Tallahatchie Bridge). Some also thought of it as a "Women's Lib" song along the line of Reddy's other hits, like her other #1's, "I Am Woman" and "Delta Dawn," though O'Day says that that was not his intent, and that he was not consciously making a public statement.

The song was also featured as the sole Helen Reddy track as part of a promotional-only compilation album issued by Capitol Records entitled "The Greatest Music Ever Sold" (Capitol SPRO-8511/8512), which was distributed to record stores during the 1976 Holiday season as part of Capitol's "Greatest Music Ever Sold" campaign, promoting 15 "Best Of" albums that were released by the record label.

"Angie Baby" became Helen Reddy's first charting single in the British Isles reaching #5 in both the UK and Ireland in February 1975; Reddy would chart again once in both nations with "I Can't Say Goodbye to You" - (#43 UK/ #16 Ireland) - in 1981. [1] "Angie Baby" was also Reddy's final major hit in her native Australia at #13.

Alan O' Day recorded his composition for his 1977 album Appetizers. "Angie Baby" has also been recorded by Barbara Dickson.