Nancy Sandra Sinatra (born June 8, 1940) is an American singer and actress. She is the daughter of Frank Sinatra and is widely known for her 1966 signature hit "These Boots Are Made for Walkin'".

Other defining recordings include "Sugar Town", the 1967 number one "Somethin' Stupid" (a duet with her father), the title song from the James Bond film You Only Live Twice, several collaborations with Lee Hazlewood such as "Jackson", and her cover of Cher's "Bang Bang". Nancy Sinatra began her career as a singer and actress in November 1957 with an appearance on her father's ABC-TV variety series, but initially achieved success only in Europe and Japan. In early 1966 she had a transatlantic number-one hit with "These Boots Are Made for Walkin'". She appeared on TV in high boots, and with colorfully dressed go-go dancers, creating a popular and enduring image of the Swinging Sixties. The song was written by Lee Hazlewood, who wrote and produced most of her hits and sang with her on several duets, including the critical and cult favorite "Some Velvet Morning". In 1966 and 1967, Sinatra charted with 13 titles, all of which featured Billy Strange as arranger and conductor.

Sinatra also had a brief acting career in the mid-1960s including a co-starring role with Elvis Presley in the movie Speedway, and with Peter Fonda in The Wild Angels. In Marriage on the Rocks, Frank and Nancy Sinatra played a fictional father and daughter.