The Parsley massacre was a mass killing of Haitians living in the Dominican Republic's northwestern frontier and in certain parts of the contiguous Cibao region in October 1937. Dominican Army troops from different areas of the country carried out the massacre on the orders of Dominican dictator Rafael Trujillo. As a result of the massacre, virtually the entire Haitian population in the Dominican frontier was either killed or forced to flee across the border. Many died while trying to flee to Haiti across the Dajabón River that divides the two countries on the island; the troops followed them into the river to cut them down, causing the river to run with blood and corpses for several days. The massacre claimed the lives of an estimated 14,000 to 40,000 Haitian men, women, and children. Dominican troops interrogated thousands of civilians demanding that each victim say the word "parsley" (perejil). If the accused could not pronounce the word to the interrogators' satisfaction, they were deemed to be Haitians and killed.

The Dominican Republic is a country on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean Sea, bordered by the Atlantic Ocean to the north. It occupies the eastern five-eighths of the island, which it shares with Haiti, making Hispaniola one of only two Caribbean islands, along with Saint Martin, that is shared by two sovereign states. It is the second-largest nation in the Antilles by area at 48,671 square kilometers (18,792 sq mi), and second-largest by population, with approximately 11.4 million people in 2024, of whom approximately 3.6 million live in the metropolitan area of Santo Domingo, the capital city.