Robert A. Millikan Senior High School is a high school in Long Beach, California, United States, administered by the Long Beach Unified School District. It is located near the intersection of Spring Street and Palo Verde Avenue in the Los Altos neighborhood of East Long Beach on a 36-acre campus. Millikan High School has around 3,500 students. Millikan is an AP school and does not offer IB courses.

Millikan High School is named after the Nobel Prize winner Robert Andrews Millikan.

The choral program consists of six courses: Choraleers Singers 1–2 which is a freshman girls class; Varsity Chorale 1–8, a freshman boys class; Cecillian Singers 3–8, an intermediate girls class; Concert Choir 1–8, a large, advanced, Co-Ed group of vocalists consisting of 100 singers; Vocal Point, a jazz and a cappella female group, sung on microphone; and Vocal Ensemble, the Co-Ed equivalent of Vocal Point.

The instrumental music program consists of Gold Jazz Band, Blue Jazz Band, Symphonic Winds, Concert Band, Marching Band, Orchestra, Chamber Orchestra, and Symphonic Orchestra.

Each year the music ensembles compete in festivals throughout the United States. In recent years Millikan musicians have traveled to compete in festivals in San Francisco, San Diego, Las Vegas and Reno. In the spring of 2006, the Symphonic Orchestra performed in a national festival at the Historic Boston Symphony Hall in Boston, Massachusetts.

Millikan teams include Cross Country, Tennis, Badminton, Water Polo, Dance, Football, Colorguard, Golf, Surf, Marching Band, Basketball, Volleyball, Beach Volleyball, Soccer, Wrestling, Baseball, Gymnastics, Swim, Softball, Track, Water polo, Lacrosse, and Cheer Some sports are co-ed while others are not. 2018 marked the first year for a female to score a point for the Millikan Rams varsity football.

Millikan's newspaper is The Corydon. It has been running since 1956.

This article's list of alumni may not follow Wikipedia's verifiability policy. Please improve this article by removing names that do not have independent reliable sources showing they merit inclusion in this article AND are alumni, or by incorporating the relevant publications into the body of the article through appropriate citations. (June 2020)

• Susie Atwood, double Olympic medalist, 1972 Olympics, backstroke
• Ryan Bailey, Olympic water polo player
• Greg Barton, NFL player
• Jason Bell, NFL player
• Jennifer Bermingham, professional golfer
• Nick Bierbrodt, baseball player
• Ron Brown, NFL player
• Courtney Clements, former WNBA player
• Alden Darby, NFL player
• Tacario Davis, college football cornerback for the Arizona Wildcats
• Marcus Dove, basketball player
• Audie England, Actor
• Dave Frost, professional baseball player
• Mike Gallo, professional baseball player
• Gary Garrison, professional football player with San Diego Chargers
• Bud Gaugh, Sublime Drummer.
• Jack Grisham, TSOL vocalist, author An American Demon: A Memoir
• Gene Hoglan, metal musician
• Soben Huon, Miss Utah USA 2006
• Wendi McLendon-Covey, actress on ABC's The Goldbergs, actress on Comedy Central's Reno 911!, and the film Bridesmaids
• Charles McShane, NFL player
• Mike Montgomery, Golden State Warriors and University of California basketball coach
• Tino Nuñez, professional soccer player
• Syd O'Brien, professional baseball player
• Brent Poppen, author, motivational speaker and Paralympian
• Dante Powell, professional baseball player
• Greg Sampson, football player, sixth pick of 1972 NFL draft
• Chris Saunders, UFC, The Ultimate Fighter: Live - Season 15
• Ann Simmons, Olympic competition swimmer
• Jonathan Singleton, professional baseball player
• Spencer Steer, professional baseball player
• Craig Swan, professional baseball player
• John Tautolo, NFL player
• Terry Tautolo, NFL player
• Mike Tully, pole vaulter, 1984 Summer Olympics silver medalist
• Brian Turang, professional baseball player
• Greg Williamson, professional football player