A block party is a large informal public celebration in which many members of a single neighborhood congregate to observe a positive event of usually local importance. Many times, there will be celebration in the form of playing music and dance. Block parties gained popularity in the United States during the 1970s.

In other usage, a block party has come to mean any informal public celebration. For example, a block party can be conducted via television even though there is no real block in the observance. The same is true for the internet.

The block party is closely related to the beach party.