Roller derby is basically a contact sport and historically a form of sports entertainment based on development roller skating around an oval track. During the past roller derby had been primarily a professional or paid sport for both women and men. Contemporary roller derby is predominantly female, typically operates on an amateur circuit and has a strong do it yourself ethic which often features both athleticism and a satirical feminist punk aesthetic.

Roller Derby is played by professional teams as well as amateur teams. Roller Derby has turned into mostly a sport for women players. The rules of Roller Derby vary between leagues, but usually two teams of five players each skate pack-style counter-clockwise around a thin track. The two positions in Roller Derby are blockers and jammers and the pivots are blockers that set the initial pace at the start of the Roller Derby.

Jammers in Roller Derby try to get through the pack and the first one who does is the lead jammer. The lead jammer has the right to stop the jam, and the decision to do so is considered a strategic one in Roller Derby. Points are scored in Roller Derby when the jammers go through the pack a second time. Blockers do their best to stop the opposing jammers, but they also have to help their own jammers move through the pack by doing what is known as whipping. Whipping means pulling or pushing the jammers and the jam is over either when it is called off by the lead jammer, or when a set period of time is reached such as two minutes. Helmet covers are used to display the players' positions: a striped cover is used for pivots, a cover with two stars is used for jammers, and no cover is used for blockers.

Most current roller derby leagues use rules set by the Women's Flat Track Derby Association.

All-female, grassroots leagues:

Nearly all contemporary roller derby leagues are all-female and self-organized, and furthermore were formed in an indie, DIY spirit by relatively new roller derby enthusiasts. These leagues deploy traditional quad roller skates, and a punk aesthetic and/or ethic is often prominent. Many if not most are legally incorporated as limited liability companies and a few are non-profit organizations, and most compete on flat tracks.

Each league generally features two or more local teams which compete in public matches, called bouts, for a diverse fanbase. Members of fledgling leagues often practice and strategize together, regardless of team affiliation, between bouts. Moreover, as the business and infrastructure of the sport matures, successful local leagues form travel teams to compete with the roller derby leagues of other cities and states.