Loose socks are a style of baggy sock popular with Japanese high school girls.

They were adopted as a fashion which flattered plump calves and also expressed rebellious deviation from Japan's strict dress code for school uniforms. They were first worn by high school girls and later by junior high school girls who sought to emulate the look of the older female students, but are generally not worn by young adults and older women.

They are nearly always white, though black and navy blue ones also exist. Generally, they are larger than normal socks. To wear them, one stretches them out and puts them on. They are usually worn below the knee, held up with a special adhesive sock glue, and resemble leg warmers. Loose socks are often paired with skirts above the knee and a pair of mary janes or loafers.