Prosser High School is a school in Prosser, Washington. It is the main high school in the Prosser School District, though there is also an alternative Prosser Falls Education Center. The school has around 920 students attending in grades 9 through 12. The mascot is the Mustang and the school colors are red and white.
The school district has been trying to build a new, larger high school to replace the existing campus, which was built in 1936. The current campus is overcrowded and run-down, with about 900 students attending a facility built for 500 students. District officials have held bond elections three times so far, once in 2005 and again in February and April 2011, in an attempt to get voter approval of a new school. However, all three elections failed to reach the 60 percent supermajority required for passage.