National Good Neighbor Day is a national holiday in the United States that is celebrated annually on the fourth Sunday in September. In 2003, the annual day of celebration was changed from the fourth Sunday in September to September 28.
In the early 1970s, Becky Mattson of Lakeside, Montana created National Good Neighbor Day as a day to connect with and recognize the importance of good neighbors. On September 22, 1978, President Jimmy Carter signed Proclamation 4601 establishing September 24, 1978 as National Good Neighbor Day, stating that it should be observed "with appropriate ceremonies and activities."
On April 28, 2004, the Senate passed a resolution by Montana Senator Max Baucus to designate September 26 as National Good Neighbor Day.