Dollar Tree's closing time varies by location, but some common closing times are 9 p.m. or 10 p.m. Monday through Saturday and 8 p.m. or 9 p.m. on Sundays. The opening times also vary but are commonly 8 a.m. or 9 a.m. every day. The Dollar Tree website's store locator can be used to find the exact opening and closing hours for a particular location.