Fraser was born in Southwark, London. Her year of birth was usually attributed as 1933, which she gave when auditioning for her role in I'm All Right Jack, as the Boulting Brothers wanted someone younger for the part. She is actually three years older, confirmed in her autobiography, Liz Fraser ... and Other Characters, published by Signum Books in 2012. Her father was a travelling salesman for a brewery and her mother owned a shop just off the New Kent Road. Family life was disrupted by the Second World War when she was evacuated, initially to Westerham in Kent and then, when that was deemed still too vulnerable to the bombs, to Chudleigh, a village in Devon. Her father died in May 1942, aged 40, when she was 11.
She attended St Saviour's and St Olave's Grammar School for Girls between the ages of 13 and 17, and also attended Goldsmiths College in the evenings, where she had joined a drama group. On leaving school she attended the City of London College for Commerce, Book-Keeping, Shorthand and Typing and won an evening scholarship to the London School of Dramatic Art.
Fraser is known for her many appearances in British films and television series, including Hancock's Half Hour, Last of the Summer Wine and The Avengers episode "The Girl from Auntie". As Elizabeth Fraser, over a period of nearly six months, she appeared in numerous editions of the Associated-Rediffusion soap opera Sixpenny Corner (1955–56). She played Mrs Brent, a dead/missing girl's mother, in Nemesis – one of the Joan Hickson Miss Marple episodes for the BBC in 1987. She gave a strong and memorable performance in The Professionals episode "Backtrack" first broadcast in 1979 as Margery Harper (Marge) a fairly glamorous lady who fenced stolen property in her shop.
She appeared on Benny Hill's late-1950s TV shows, and in a single sketch in the 23 December 1970 episode of his Thames TV series. As this episode was in black & white (due to the "colour strike" by TV technicians, who wanted to be paid extra for working with the then-new colour TV technology), the sketch was not included in any of the half-hour syndicated episodes of the Benny Hill Show. However, it is included in the Volume 1 box set of the complete Benny Hill Show, issued by A&E and Fremantle.
Her first film appearance was in Touch and Go (1955) credited as Elizabeth Frazer and The Smallest Show on Earth (1957) in which she worked with Peter Sellers for the first time. Further film appearances include I'm All Right, Jack (1959) for which she received a BAFTA nomination as Most Promising Newcomer, Two-Way Stretch (1960), The Bulldog Breed (1960), Double Bunk (1961) The Painted Smile (1962). The Americanization of Emily (1964), The Family Way (1966), Dad's Army (1971), the sex comedies Adventures of a Taxi Driver (1976), Confessions of a Driving Instructor (1976), Adventures of a Private Eye (1977) and Rosie Dixon – Night Nurse (1978), and four of the Carry On films: Carry On Regardless (1961), Carry On Cruising (1962), Carry On Cabby (1963) and Carry On Behind (1975).
Her other television work has included Randall and Hopkirk (Deceased), Crown Court, Citizen James, The Bill, Foyle's War, Birds of a Feather, Minder and Holby City.
She married Peter Yonwin, a travelling salesman, in November 1958 but the marriage soon broke down and they divorced. She married her second husband, Bill Hitchcock, a TV director, in January 1965 at Harrow Register Office. They agreed not to work together, but this pact was broken in 1972 when she appeared in the Rodney Bewes sitcom Albert! and again later in the same year, when she acted in Turnbull's Finest Half-Hour a comedy series starring Michael Bates. Hitchcock died from a pulmonary embolism in February 1974 at the age of 45.
Fraser had a half-brother, Philip, 11 years older, the son of her mother from a previous marriage. Fraser has been a prolific worker for charities and is a patron of the London Repertory Company.Sixpenny Corner (1955) - Julie Perkins
Hancock's Half Hour (1956) - Muriel / Woman on restaurant counter / Girl in cafe / Various Characters
Citizen James (1960-1962) - Liz
The Avengers: "The Girl from AUNTIE" as Georgie Price-Jones (1966) - Georgie Price-Jones
Mickey Dunne (1967) - Maisie
"Randall and Hopkirk (Deceased)" (1969): "It's Supposed to be Thicker than Water" - Fay Crackan
The Goodies: "Caught in the Act" (1970)
Turnbull's Finest Half-Hour (1972) - Faye Bush
The Professionals: "Backtrack" (1979) - Margery Harper
3-2-1: "Medicine" (1979) - Herself
Fairly Secret Army (1984–1986) - Doris Entwhistle
Miss Marple (TV series) (1987) - Mrs. Brent
Birds of a Feather: "Just Family" (1991) - Olive Stubbs
Minder: "How to Succeed in Business Without Really Retiring" (1993) - Delilah
Last of the Summer Wine (2000) - Reggie Unsworth
Doctors (2006) - Beryl Gifford
Foyle's War (2007) - Mollie Summersgill
Holby City (2007) - Tabitha Blackstock