Charles Francis "Charlie" Harper is a fictional character and one of the two main protagonists in the CBS sitcom Two and a Half Men during the first eight seasons of the series. Played by actor Charlie Sheen, the character of Charlie Harper is loosely based on Sheen himself. The show has garnered him four Primetime Emmy Award nominations for Outstanding Lead Actor in a Comedy Series and two Golden Globe nominations for Best Performance by an Actor in a Comedy Series. Although the character was written off after the end of the eighth season, the character was reprised for one episode of the ninth season by Kathy Bates, which resulted in her winning the Primetime Emmy Award for Outstanding Guest Actress in a Comedy Series and in the series finale, "Of Course He's Dead".

After being expelled from Juilliard School, Charlie moved back to Los Angeles with the intention of becoming a film composer. He met a commercial producer who listened to Charlie's work; thus began his career writing jingles. His most famous composition is the Maple Loops song. He then became a successful composer and singer of children's music under the alias "Charlie Waffles" when the jingle business dried up. He can be frequently seen playing the Steinway grand piano in his living room. The piano was later removed from the house by Walden Schmidt.

Charlie prides himself on his bachelor/playboy lifestyle in Malibu, California and drives a Mercedes, and used to own a Jaguar. He was also thinking of buying a Ferrari F430 or a Bentley. His lifestyle consists of living in a two-story beachfront house, drinking excessively, smoking cigars, womanizing and gambling constantly, and wearing shorts and bowling shirts. He sleeps in constantly and retains a full-time housekeeper, Berta. Money "falls into his lap" as he lives a life of free-spirited debauchery. He has a vast range of phobias, including stage fright (unless he is drunk), commitment, his mother, spiders, large birds, germs, change, and hard work.

Following Sheen's dismissal from the series in March 2011, the character was written off in the ninth season, with his wife Rose implying he was killed by a train in Paris while on vacation. Charlie's ghost, portrayed by Kathy Bates, returns as a hallucination to Alan, revealing that he is living in Hell trapped in a woman's body. However, in the series finale, "Of Course He's Dead," Rose reveals that Charlie had been alive all along (albeit brainwashed) and she was keeping him prisoner in the basement of a house that she purchased in Sherman Oaks after returning to the United States. He escapes from Rose's basement and returns to the beach house. As he rings the doorbell, a piano that is being transported by helicopter falls from the sky, killing him.

Both the character and Sheen's portrayal received a positive reception, with critics and fans feeling he was the best character on Two and a Half Men.

When Charlie's mother Evelyn was pregnant with him (for 7 and a half months), his parents thought that he was going to be a girl, since the ultrasound showed no signs of a penis. According to Evelyn, Charlie was always "a little drama queen" when he grew up. After his father died of food poisoning, Charlie and his brother Alan had three stepdads. The first, Harry Luther Gorsky, left Evelyn for a young woman (Charlie refers to Harry as "a little tyrant"), and Evelyn was also present at his funeral, the second was a twitchy gay man from Texas who called him and Alan "buckaroos", and the third was "the Carpet King", a fat man whom Charlie liked the most because he had "a grateful daughter". Well into his 40s, Charlie believed "the Carpet King" owned a carpeting business until his mother explained that the man's name was actually sexual slang rather than his profession.

When Charlie was young, he was embarrassed by his younger brother Alan; on Alan's first-ever day of school, Charlie told everyone at school that Alan was his shaved monkey (he later explained he did this because he always wanted a shaved monkey). He also gave his brother frequent wedgies and bullied him whenever he could. Charlie has dependably had a troubled association with Alan, and would go to all expenses to escape being a decent sibling to him. As a child, Charlie once put a toy in Alan's pocket to shop-lift, and when they got caught, he influenced Alan to assume the fault. Charlie drank a lot when he was a teenager, was a chain smoker, and constantly ran away, nevertheless his mother did not mind because he always came back, and generally did not care about her sons. He once even, when he was 16, drove to Tijuana, Mexico with a school nurse. When he was 17, he almost married a woman whom he thought was the love of his life, but relented. Charlie says that if he did not, he would at that point be married to a "65-year-old retired belly dancer". Charlie constantly criticizes Alan and Jake's presence in his house, but generally seems happy that they are around, because they are the only people who have known him for a long time and accept his unconventional life. When Alan was surprised to find that Charlie did not have their mother's cell phone number in his contacts list, Charlie told him "If I can't eat it, bang it or bet on it, it's not in my phone." On a later episode, it is shown Charlie does have his mother's number. He has it on the speed dial address that he finds appropriate for her, "666".

Charlie and Alan have an estranged relationship with their mother and try to avoid her at all costs; Charlie refers to her as "a Satan". Not much is known about their biological father, Francis Harper, except that when Charlie thinks back he says he was a horrible son to him. Evelyn, even after multiple marriages, still keeps her first husband's name (Harper). Charlie also once had a hallucination of his father Francis telling him to take care of his mother, which horrified him, but when he saw an old gangster film, he realized that he "misunderstood"; his father actually wants him to kill her when he can manage this.