The name was popularized by a film series made in the 1950s and 1960s about a lovable backwoods girl named Tammy Tyree.
Tammy was most popular as a girl's name in the United States in the 1950s, when it was the 140th most popular name given to girls; in the 1960s, when it was the 13th most popular name for girls; and in the 1970s, when it was the 23rd most popular name for girls. It remained well-used throughout the 1980s and into the mid-1990s. It has not been ranked among the top 1,000 names for girls born in the United States since 1998. It was the 75th most common name for all females in the United States in the 1990 census. It was ranked as the 959th most popular name for boys born between 1960 and 1969 in the United States, but has not appeared among the top 1,000 names for boys there since the 1960s.