Dennis-Yarmouth Regional High School is a suburban public high school (grades 8–12) in Yarmouth, Massachusetts, United States. It opened in 1957 and was expanded and renovated in 1963, 1977, and 2006. The school serves the communities of Yarmouth and Dennis, and had an enrollment of 993 students in the 2024-2025 school year. Dennis-Yarmouth, or known more commonly to the locals as "D-Y", is the second largest high school (in terms of student population) on Cape Cod, behind only Barnstable High School. It is in South Yarmouth, just south of the Mid Cape Highway.