Tomboy is a term used to describe a girl or woman who exhibits characteristics or behaviors considered typical of a boy. This may include wearing masculine clothing and engaging in physical activities often associated with boys. Tomboyish girls are often seen as free-spirited, tough, and independent. They may also be more reserved than their peers.

The concept of the "tomboy" has evolved over time. The term was originally associated with "boys and men who are boisterous, forward, or rude" in the 14th century, thus its namesake, but quickly became associated with girls within half a century, now associated with "girls and women who are bold or immodest". In the 19th century, it was rooted in societal concerns about white women's health and their roles in marriage and motherhood. Later, it became associated with third wave feminism and the rejection of traditional gender roles.

Some tomboys identify as part of the LGBTQ+ community, particularly with Butch/Stud lesbianism. Tomboyism often rejects traditional gender norms for girls and women, who identify with a more masculine identity. However, one does not have to be LGBTQ+ to be a tomboy; anyone of any background, lifestyle, and orientation can be a tomboy.

Tomboyish fashion consists of feminine outfits modeled after masculine fashions. Things such as:

Often times, however, it can be paired with more feminine fashion accessories, such as golden hoop earrings.

Contrary to popular belief, many tomboyish girls still like shopping, albeit usually not at the same stores or types of stores as girls who express themselves in a traditionally feminine manner. However, there can sometimes be overlap.

Tomboyish-styled makeup can be anywhere from none at all to heavy. Some makeup styles can include:

Popular tomboyish hairstyles include messy buns, short cuts, naturals, and ponytails.

Contrary to popular belief, not all tomboyish girls are "dumb" or hate school. Many tomboyish girls like academic subjects that involve action or adventure such as history, geography, geology, biology, manufacturing and construction, paleontology, astronomy, anthropology, archaeology, and photography. Some of them also like action and adventure books as well as comic books (specifically the superhero, sci-fi, western, western sci-fi, military sci-fi, space western, swashbuckler, urban fantasy, high fantasy, dark fantasy and science fantasy genres), shonen and seinen-targeted Japanese media in addition to western media targeted towards boys and older men, playing with toys often marketed towards boys such as action figures, plastic model kits, model vehicles, remote controlled vehicles, yo-yos, toy weapons such as guns, bows and arrows, spears and swords, and construction sets (primarily Lego) as well as technology, painting and engineering.