A sex toy is an object or device that is primarily used to facilitate human sexual pleasure. The most popular sex toys are designed to resemble human genitals and may be vibrating or non-vibrating. The term can also include BDSM apparatus and sex furniture such as slings, however it is not applied to items such as contraceptives, pornography, or condoms.

Alternative expressions include adult toy and marital aid, although "marital aid" has a broader sense and is applied to drugs and herbs marketed to supposedly enhance or prolong sex.