Swinging or (rarely) partner swapping is a non-monogamous behavior, in which singles or partners in a committed relationship engage in sexual activities with others as a recreational or social activity.

Swinging can take place in a number of contexts, ranging from spontaneous sexual activity at informal gatherings of friends to planned regular social meetings to hooking up with like-minded people at a swingers' club. It can also involve Internet-based swinger social networking services online.

The older term wife-swapping, once considered to be equivalent to "swinging," is criticized today as being androcentric where it is presumed that the partners are a married heterosexual couple and that it is the male who is in control of the sexual activities and also that it does not accurately describe the full range of sexual activities in which both singles or couples may take part.

Note: Do not confuse swinging with Adultery.