Carry On is a British comedy franchise comprising 31 films, the success of which led to several spin-offs, including four Christmas television specials (1969–1973), a 1975 television series of 13 episodes, a West End stage show and two provincial summer shows, produced between 1958 and 1992. Produced by Peter Rogers, the Carry On films were directed by Gerald Thomas and starred a regular ensemble that included Sid James, Kenneth Williams, Charles Hawtrey, Joan Sims, Kenneth Connor, Peter Butterworth, Hattie Jacques, Terry Scott, Bernard Bresslaw, Barbara Windsor, Jack Douglas, and Jim Dale. The humour of Carry On was in the British comic tradition of music hall and bawdy seaside postcards.

The Carry On series contains the largest number of films of any British film franchise, and is the second longest running, albeit with a 14-year gap (1978–1992) between the 30th and 31st entries. (The James Bond film series is the longest-running, having started in 1962, four years after the first Carry On, though with fewer films.)

Rogers and Thomas were responsible for all 31 films, usually on time and to a strict budget, and often employed the same crew—some of whom were also regulars on the James Bond series, such as Peter Lamont, Alan Hume, and Anthony Waye. Between 1958 and 1992, the series employed seven writers, most often Norman Hudis (1958–1962) and Talbot Rothwell (1963–1974). Anglo Amalgamated Film Distributors Ltd produced 12 films (1958–1966), and the Rank Organisation made 18 (1966–1978), while United International Pictures produced one (1992).

All films were made at Pinewood Studios near Iver Heath, Buckinghamshire. Budgetary constraints meant that a large proportion of the location filming was undertaken close to the studios in and around south Buckinghamshire, including areas of Berkshire and Middlesex. However, by the late 1960s, at the height of the series' success, more ambitious plots occasionally necessitated locations further afield, which included Snowdonia National Park, Wales (with the foot of Snowdon standing in for the Khyber Pass in Carry On Up the Khyber), and the beaches of the Sussex coast doubling as Saharan sand dunes in Follow That Camel.

Carry On Sergeant (1958) is about a group of recruits doing National Service; its title, a command commonly issued by army officers to their sergeants in the course of their routine duties, was in keeping with its setting. The film was sufficiently successful to inspire a similar venture, again focusing on an established and respected profession in Carry On Nurse. When that too was successful, further forays with Carry On Teacher and Carry On Constable established the series. This initial 'pattern' was broken with the fifth film in 1961, Carry On Regardless, but it still followed a similar plot to that of many of the early films—a small group of misfit newcomers to a job make comic mistakes, but come together to succeed in the end.

The remainder of the series developed with increased use of the British comic traditions of music hall and bawdy seaside postcards. Many titles parodied more serious films, such as their tongue-in-cheek homages to James Bond (Spying), westerns (Cowboy), and Hammer horror films (Screaming!). The most impressive of these was Carry On Cleo (1964), in which the budget-conscious production team made full use of some impressive sets that had been created in 1960 for the Burton and Taylor epic Cleopatra (1963) but abandoned when production moved to Rome. Carry On Emmannuelle, inspired by the soft-porn Emmanuelle, brought to an end the original Carry On run.

The stock-in-trade of Carry On humour was innuendo and the sending-up of British institutions and customs, such as the National Health Service (Nurse, Doctor, Again Doctor, Matron and the proposed Again Nurse), the monarchy (Henry), the Empire (Up the Khyber), the armed forces (Sergeant, England, Jack and the proposed Flying and Escaping), the police (Constable) and the trade unions (At Your Convenience) as well as camping (Camping), foreign holidays (Cruising, Abroad), beauty contests (Girls), caravan holidays (Behind), and the education system (Teacher) amongst others. Although the films were very often panned by critics, they mostly proved very popular with audiences. In 2007, the pun "Infamy, infamy, they've all got it in for me", spoken by Kenneth Williams (playing Julius Caesar) in Carry on Cleo, was voted the funniest one-line joke in film history. However, this line had originally been written by Frank Muir and Denis Norden for Jimmy Edwards in the radio series Take It From Here some years previously.

A film had appeared in 1957 under the title Carry On Admiral; although this was a comedy in similar vein (and even featured Joan Sims in the cast) it has no connection to the Carry On series itself. The much earlier 1937 film Carry On London is also unrelated (though it coincidentally starred future Carry On performer Eric Barker).