A motorcycle helmet is a type of protective headgear used by motorcycle riders. The primary goal of a motorcycle helmet is motorcycle safety - to protect the rider's head during impact, thus preventing or reducing head injury or saving the rider's life. Some helmets provide additional conveniences, such as ventilation, face shields, ear protection, intercom etc.

The Snell Memorial Foundation has developed stricter requirements and testing procedures for motorcycle helmets with racing in mind, as well as helmets for other activities (e.g. drag racing, bicycling, horseback riding), and many riders in North America consider Snell certification a benefit when considering buying a helmet while others note that its standards allow for more force (g's) to be transferred to a rider's head than the U.S. Department of Transportation (DOT) standard. However, the DOT standard does not test the chin bar of helmets with them, while the Snell (and ECE) standards do. A motorcycle helmet with either standard will nonetheless provide vastly more protection than no helmet at all.

In the United Kingdom, the Auto-Cycle Union (ACU) defines a stricter standard for racing than the legal minimum ECE 22.05 specification. Only helmets with an ACU Gold sticker are allowed to be worn in competition, or at track days. Many riders in the UK choose helmets with an ACU Gold sticker for their regular on-road use.
There are other types of headwear - often called "beanies," "brain buckets", or "novelty helmets", a term which arose since they cannot legally be called motorcycle helmets. These helmets are not certified and are generally only used to provide the illusion of compliance with mandatory helmet laws. Such items are often smaller and lighter than helmets made to DOT standards, and are unsuitable for crash protection because they lack the energy-absorbing foam that protects the brain by allowing it to come to a gradual stop during an impact. A "novelty helmet" can protect the scalp against sunburn while riding and - if it stays on during a crash - might protect the scalp against abrasion, but it has no capability to protect the skull or brain from an impact.

There are other types of headwear - often called "beanies," "brain buckets", or "novelty helmets", a term which arose since they cannot legally be called motorcycle helmets. These helmets are not certified and are generally only used to provide the illusion of compliance with mandatory helmet laws. Such items are often smaller and lighter than helmets made to DOT standards, and are unsuitable for crash protection because they lack the energy-absorbing foam that protects the brain by allowing it to come to a gradual stop during an impact. A "novelty helmet" can protect the scalp against sunburn while riding and - if it stays on during a crash - might protect the scalp against abrasion, but it has no capability to protect the skull or brain from an impact.