Bystander intervention is a type of training used in post-secondary education institutions to prevent sexual assault or rape, binge drinking and harassment and unwanted comments of racist, homophobic, or transphobic nature. A bystander is a person who is present at an event, party, or other setting who notices a problematic situation, such as a someone making sexual advances on a drunk person. The bystander then takes on personal responsibility and takes action to intervene, with the goal of preventing the situation from escalating.

The bystander who is intervening has several options, including distracting either of the people, getting help from others, checking in later, or directly intervening. There are risks to bystander intervention; it can lead to fights, it can ruin the mood for the people who were "intervened" into, and it can lead to confrontations. Bystander intervention may also be called "bystander education", because the model is based on a system of educating trainers and leaders who will then go on to train people from their community.