Tyler Alan O'Neill (born June 22, 1995) is a Canadian professional baseball outfielder for the St. Louis Cardinals of Major League Baseball (MLB). He made his major league debut on April 19, 2018. He has represented Canada in international play, winning a gold medal at the 2015 Pan American games. O'Neill stands 5 feet 11 inches (1.80 m) tall, weighs 210 pounds (95 kg), and throws and bats right-handed.
From the Greater Vancouver area of British Columbia, the Seattle Mariners selected O'Neill in the third round of the 2013 amateur draft. In 2016, he was the Southern League Most Valuable Player (MVP) along with winning the Southern League championship with the Jackson Generals. On July 21, 2017, the Mariners traded him to the Cardinals. Later that year, he won the Pacific Coast League championship as a member of the Memphis Redbirds.
He is also known as Tyler Alan O'Neill.