Peter Brian Walker (born April 8, 1969 in Beverly, Massachusetts) is a former right-handed relief pitcher in Major League Baseball. Walker is a graduate of East Lyme High School in East Lyme, Connecticut. He completed his college degree at Charter Oak State College. He attended the University of Connecticut and was drafted by the New York Mets in 1990. Walker made his MLB debut for them in 1995.

On March 17 1996, Walker was traded along with minor leaguer Scott Adair to the San Diego Padres for Roberto Petagine and minor leaguer Luis Arroyo. Walker would then go on to play only one game for the Padres before going to the minors. In 1997, Walker signed with the Boston Red Sox, but never played for them at the major league level.

In 2000, Walker made his way back to the major league level with the Colorado Rockies after signing with them in 1998. In December 2000, Walker once again signed with the New York Mets playing 3 games for them before returning to the minors. On May 3, 2002, he was picked off waivers by the Toronto Blue Jays, he would go on to play 124 games for the Blue Jays between 2002 and 2006.

On July 22, 2006, Walker had shoulder surgery. In 2006, the Toronto Blue Jays released him, but on February 12 2007, the Blue Jays signed him to a minor league contract with an invitation to spring training where he was later released towards the end of spring training 2007 in the hopes that another team would pick up his contract, that team would be the New York Yankees. He signed with them on May 9, 2007.

On November 7, 2011, Peter Walker was named bullpen coach for the Toronto Blue Jays, following a stint as the pitching coach for double-A New Hampshire, which won the Eastern League title earlier that year.