"I take a lot of pride in the success we have had, and that's the result of a lot of hard work and commitment," he wrote. "I'm graduating from UCLA and looking forward to the next step in my basketball career. With aspirations to play professionally, I am declaring for the NBA Draft."
Campbell was a mainstay in Westwood for the past four seasons after missing his freshman year with a knee injury.
The senior from Cedar Rapids, Iowa, averaged 13.4 points, 5.0 assists and 2.6 rebounds while playing all 37 games this past season. Campbell led the Pac-12 in assist-turnover ratio (3.2) and also finished third in the nation in that category. He also led the league in free-throw percentage at 85.6.
He finished second on the school's all-time assists list with 655 and 10th in games played at 133.
Campbell earned first-team All-Pac-12 honors for three years and was an honorable mention this past season.
He helped the Bruins reach the Final Four in 2021 and the Sweet 16 in 2022 and this year.
"This was an emotional last run for the two of us, as we both worked so hard together to make UCLA elite again," coach Mick Cronin said in a statement. "We know that Tyger has a long future in pro basketball, and I hope that I'm coaching long enough to hire him on my staff someday, as well."
Campbell and teammate David Singleton, who is out of eligibility, are set to compete in the Portsmouth Invitational this week, a pre-draft showcase in Virginia.
Jaquez, a senior, is headed to the draft after deciding to forgo an extra year of eligibility available because of the COVID-19 pandemic.
Clark, a junior, has said he will enter the draft. However, he did not indicate whether he would hire an agent ahead of the June 22 draft or retain his remaining eligibility.