Thomas James Pham (born March 8, 1988) is an American professional baseball outfielder in the Philadelphia Phillies organization. He has previously played in Major League Baseball (MLB) for the St. Louis Cardinals, Tampa Bay Rays, San Diego Padres, Cincinnati Reds, Boston Red Sox, New York Mets, Arizona Diamondbacks, Chicago White Sox, Kansas City Royals, and Pittsburgh Pirates.

Pham was selected by the Cardinals in the 16th round of the 2006 MLB draft. After a number of injuries and a vision impairment in 2008 related to keratoconus (which he overcame the following year with contact lenses that give him 20/15 vision in both eyes) he made his MLB debut nine seasons after being drafted. In 2017, Pham became the first Cardinals batter since 1900 to record at least a .300 batting average, 20 home runs, 20 doubles, and 20 stolen bases in the same season.

Pham was born in Las Vegas, Nevada, to Tawana (age 17) and Anhtuan (age 19). His twin sister Brittany was born two minutes later. At the time, his father was incarcerated. His father was born in Vietnam to a Vietnamese mother and an African American father, and moved to the United States with his mother, brother, and sister. Pham's father was gifted in American football, but became entangled in drugs and street crime for decades.

Pham's mother's parents helped her raise her twins on the condition that she work. She had not finished high school, and took on jobs as a busser, a casino waitress, and at a bakery, and raised the twins in Spring Valley, Nevada. At the age of two, Pham's pediatrician feared that he had contracted rickets, so he wore leg braces for a year and a half. Because his mother worked so much, Pham said he could "count on one hand" the number of his games she attended.

When he was five years old, his mother married an electrician named Fred Polk, and they had a daughter, Mercedes. Pham "has had issues" with his stepfather. He says that when he was 25 years old, the two got into a fight, and his stepfather stabbed him.

Pham attended Gorman High School, Centennial High School, and then Durango High School in Las Vegas, where he played baseball as a pitcher and infielder. As a senior, Pham was named the Class 4A All-State Player of the Year by the Reno Gazette-Journal and a second team All-American, after batting .581. With a fastball in the 90–92 mph (145–148 km/h) range, he drew interest as a pitching prospect, but he did not like to pitch, and rarely did so his senior year.

Pham originally committed to play college baseball at Arizona. He then switched his commitment to Cal State Fullerton. Ultimately, he did not attend either school. After the St. Louis Cardinals selected him in the 16th round of the 2006 amateur draft, Pham instead opted for professional baseball over college. He received a $325,000 signing bonus, higher than most players drafted as late as the 16th round.

Pham began his minor league career in 2006 batting .231/.340/.324 with one home run in 216 plate appearances, with the Rookie League Johnson City Cardinals. He played shortstop, and made 22 errors in 37 games, for an .849 fielding percentage.