Carlos Joaquín Ruiz (born January 22, 1979), nicknamed "Chooch", is a Panamanian former professional baseball catcher. He played in Major League Baseball (MLB) for the Philadelphia Phillies, Los Angeles Dodgers, and Seattle Mariners. Ruiz stands 5 ft 10 in (1.78 m) tall, and weighs 215 pounds (98 kg). He bats and throws right-handed.

As a seven-year-old, Ruiz resolved to play in the big leagues after both his father and grandmother died within two weeks of each other. He made his way through the Phillies farm system from 1998 until 2006, playing at each level of Minor League Baseball (MiLB). Ruiz soon fulfilled his childhood dream, making his MLB debut with the 2006 Phillies. He battled adversity in his progression through the system, including feeling homesick, a position change, and the language barrier (he spoke Spanish, while most teammates and team officials spoke English).

Ruiz spent his first full season in MLB with the Philadelphia Phillies in 2007 and remained there until he left the Mariners, electing free agency after the 2017 season. In 2008, for his strong postseason performance, including a walk-off hit, during the Phillies playoff run that concluded with victory in the 2008 World Series, he earned the nickname "Señor Octubre" (Mr. October). Despite being one of the quietest players on the team, Ruiz was subsequently called the "heart and soul" of the Phillies, serving as a constant source of encouragement and rebuke alike to his teammates. Over the following seasons, he was a part of the core group of players that led the Phillies to five consecutive playoff appearances, from 2007 until 2011.

Ruiz had his best season in 2012, holding a batting average of over .300, earning his first appearance in the All-Star Game, and finishing in the top 30 of the NL Most Valuable Player (MVP) voting. In 2013, he began the season with a 25-game suspension for using Adderall, and subsequently spent time on the disabled list, ultimately playing in fewer than 100 games for the first time in his MLB career.

Ruiz is the only player in the history of the NL to catch four no-hitters, and one of only two catchers in all of MLB to do so (the other being Jason Varitek).

Ruiz grew up in David, Chiriquí, Panama, and was the oldest of three sons. His father was a police officer and his mother was an elementary school teacher. When he was seven years old, his father Joaquin was patrolling in his police jeep when a tire blew out, causing the vehicle to flip, throwing Joaquin into a ditch, and then crushing him when it fell on top of him. Just weeks before, his grandmother died of cancer. As a result, Ruiz became "the new father", starting work shortly thereafter as a laborer on a coffee farm to supplement the family income, and by age 10 was earning about US$3 per day. He also promised his widowed mother that he would make it to Major League Baseball to support the family. Subsequently, he began attending college to earn a degree in physical education, but dropped out shortly after he began to attend the Phillies baseball academy.

Ruiz's upbringing contributed to his approach to the game. His mother insisted that he excel academically, and would not allow him to play baseball unless he did well in school. Baseball was his first love, and he was responsible for organizing the community's games:

Ruiz's natural leadership skills flourished. As a boy, Ruiz, who had chosen to play with baseballs instead of toy cars even as a toddler, was always the one in his neighborhood to organize pickup baseball games. It was he who brought the balls and bats, and it was he who picked the teams and ordered everyone to their positions. He had an acute understanding of the game. Ruiz was made to lead, and playing catcher eventually suited him perfectly.