Trojans running back Javorius Allen, receiver Nelson Agholor and center Max Tuerk, defensive lineman Leonard Williams and defensive back-linebacker Su'a Cravens were voted to the team by league coaches.
Bruins defensive back Ishmael Adams also was a first-team choice.
Earlier Tuesday, Oregon quarterback Marcus Mariota was announced as offensive player of the year, Arizona linebacker Scooby Wright defensive player of the year, Oregon running back Royce Freeman freshman offensive player of the year, USC's Adoree' Jackson freshman defensive player of the year and Arizona's Rich Rodriguez coach of the year.
USC, Oregon and Utah each had five players among the 27 voted to the first-team offense, defense and special teams.
Oregon plays Arizona in the Pac-12 championship game Friday at Levi's Stadium in Santa Clara.
UCLA had eight players voted to the second team: quarterback Brett Hundley, offensive lineman Jake Brendel, defensive lineman Kenny Clark, defensive lineman Owamagbe Odighizuwa, linebackers Myles Jack and Eric Kendricks and defensive backs Anthony Jefferson and Fabian Moreau.
USC receiver and kick returner JuJu Smith was second team as an all-purpose player.
Other first-team offensive players: Utah running back Devontae Booker, Arizona State receiver Jaelen Strong, Oregon tight end Pharaoh Brown, Arizona State lineman Jamil Douglas, Oregon linemen Jake Fisher and Hroniss Grasu and Stanford lineman Andrus Peat.
Other first-team defensive players: Stanford lineman Henry Anderson, Utah lineman Nate Orchard, Washington lineman Danny Shelton, Washington linebackers Hau'oli Kikaha and Shaq Thompson, Oregon defensive back Ifo Ekpre-Olomu, Arizona State defensive back Damarious Randall and Stanford defensive back Jordan Richards.
Thompson also was a first-team special teams selection. Others: Utah kicker Andy Phillips, Utah punter Tom Hackett and Utah return specialist Kaelin Clay.
Jackson is the third USC player in four years to be voted freshman defensive player of the year, joining Dion Bailey (2011) and Williams (2012). Jackson made 42 tackles for USC, including four for losses. He also broke up nine passes and forced a fumble.
Jackson also played receiver, catching seven passes, two for touchdowns. He averaged 27.7 yards per kickoff return, which ranks fourth nationally, and scored on a 100-yard return against Utah.
Allen, a junior, has rushed for 1,337 yards and nine touchdowns. He also has 40 receptions, one for a touchdown.
Agholor, a junior, has 97 receptions, 11 for touchdowns. He eclipsed 100 yards receiving five times and 200 yards twice. He also returned two punts for touchdowns.
Tuerk, a junior, moved to center after starting previous seasons at guard and tackle.
Williams, a junior, has 71 tackles, including 8 1/2 for losses. The 6-foot-5, 300-pound Williams is expected to make himself available for the 2015 NFL draft.
Cravens, who moved from safety to linebacker, has a team-best 16 tackles for losses, including five sacks. He also intercepted two passes, returning one for a touchdown.
Adams, a sophomore, has 30 tackles and returned two interceptions for touchdowns for UCLA. He also returned a kickoff for a touchdown.