Gilligan's Island is an American television situation comedy created and produced by Sherwood Schwartz and originally produced by United Artists Television. The series featured Bob Denver, Alan Hale, Jr., Jim Backus, and Tina Louise, and aired for three seasons on the CBS network, from September 26, 1964, to September 4, 1967. Originally sponsored by Philip Morris & Company and Procter & Gamble, the show followed the comic adventures of seven castaways as they attempted to survive and ultimately escape from the island where they were shipwrecked. Their escape plans constantly fail because Gilligan goofs up or visitors to the island leave without sending help.

Gilligan's Island ran for a total of 98 episodes. The first season, consisting of 36 episodes, was filmed in black-and-white. These episodes were later colorized for syndication. The show's second and third seasons (62 episodes) and the three television movie sequels were filmed in color.

Enjoying solid ratings during its original run, the show grew in popularity during decades of syndication. Today, the title character of Gilligan is widely recognized as an American cultural icon.

The two-man crew of the charter boat S. S. Minnow and five passengers on a "three-hour tour" run into a tropical storm and are shipwrecked on an uncharted island somewhere in the Pacific Ocean. The island was close enough to Hawaii to clearly pick up Hawaiian AM radio transmissions on their portable receiver. Executive producer Sherwood Schwartz believed in avoiding exposition, so he composed the sea shanty-style theme song, "The Ballad of Gilligan's Isle", as a capsule summary of the castaways' predicament.

Bob Denver as Willy Gilligan, the bumbling, dimwitted, accident-prone crewman (affectionately known as "Little Buddy" by the "Skipper") of the S.S. Minnow. Denver was not the first choice to play Gilligan; actor Jerry Van Dyke was offered the role, but he turned it down, believing that the show would never be successful. He chose instead to play the lead in My Mother the Car, which premiered the following year and was canceled after one season. The producers looked to Bob Denver, the actor who had played lovable beatnik Maynard G. Krebs in The Many Loves of Dobie Gillis. None of the show's episodes ever specified Gilligan's full name or clearly indicated whether "Gilligan" was the character's first name or his last. In the DVD collection, Sherwood Schwartz states that he preferred the full name of "Willy Gilligan" for the character. Denver, on various television/radio interviews (The Pat Sajak Show; KDKA radio), said that "Gil Egan" was his choice. The actor reasoned that because everyone yelled at the first mate, it ran together as "Gilligan." In the unaired pilot episode, it is unclear whether Lovey Howell refers to Gilligan as "Stewart" or steward. On Rescue from Gilligan's Island, the writers artfully dodged Gilligan's full name when the other names are announced.

The first episode actually broadcast, "Two on a Raft," is sometimes wrongly referred to as the series pilot. This episode begins with the same scene of Gilligan and the Skipper awakening on the boat as in the pilot (cut slightly differently to eliminate most shots of the departed actors) and continues with the characters sitting on the beach listening to a radio news report about their disappearance. There is no equivalent scene or background information in the pilot, except for the description of the passengers in the original theme song. Rather than re-shooting the rest of the pilot story for broadcast, the show just proceeded on. The plot thus skips over the topics of the pilot; the bulk of the episode tells of Gilligan and the Skipper setting off on a raft to try to bring help but unknowingly landing back on the other side of the same island.

The scene with the radio report is one of two scenes that reveal the names of the Skipper (Jonas Grumby) and the Professor (Roy Hinkley); the names are used in a similar radio report early in the series. The name Jonas Grumby appears nowhere else in the series except for an episode in which the Maritime Board of Review blames the Skipper for the loss of the ship. The name Roy Hinkley is used one other time when Mr. Howell introduces the Professor as Roy Huntley and the professor corrects him, to which Mr. Howell replies, "Brinkley, Brinkley."

The plot for the pilot episode would eventually be recycled into that season's Christmas episode, "Birds Gotta Fly, Fish Gotta Talk," in which the story of the pilot episode, concerning the practical problems on landing, is related through a series of flashbacks. Footage featuring characters that had been recast was reshot using the current actors. For scenes including only Denver, Hale, Backus, and Schafer the original footage was reused.

The last episode of the show, "Gilligan the Goddess", aired on April 17, 1967, and ended just like the rest, with the castaways still stranded on the island. It was not known at the time that it was the last episode, as a fourth season was expected but then cancelled.

In its last year Gilligan's Island was the lead-in program for the CBS Monday night schedule. It was followed for the first sixteen weeks by the sitcom Run, Buddy, Run. The time slot from 7:30 to 8:30 Eastern was filled in the 1967–1968 season by Gunsmoke, moved from its traditional Saturday 10 pm time slot.

Under pressure from network president William S. Paley and his wife Babe, as well as many network affiliates and longtime fans of Gunsmoke (which had been airing late on Saturday nights), to reverse its threatened cancellation, CBS rescheduled the Western to an earlier time slot on Monday evenings. This had been Gilligan's Island's timeslot in its third season. (The show ran on Saturdays in its debut season, before moving to Thursdays in season two.) Though Gilligan's Island's ratings had slumped from 24.7 (18th) to 22.1 (22nd) out of the top 25 (possibly as the result of two timeslot shifts in two years), the series was still profitable. Nevertheless, it was cancelled at practically the last minute even though the cast members were all on vacation. Some of the cast had bought houses based on Sherwood Schwartz's verbal confirmation that the series would be renewed for a fourth season.