Colby Ryan Rasmus (born August 11, 1986 in Columbus, Georgia) is a Major League Baseball outfielder for the St. Louis Cardinals.

Rasmus played as pitcher and first baseman for Phenix City National Little League during the 1999 Little League World Series. Phenix City won the United States championship game before losing in the finals to Osaka, Japan 5-0. Rasmus finished the World Series with a batting average of .417 and a pitching record of 0-1 with 7 strikeouts.

Rasmus attended Russell County High School in Seale, Alabama. As a senior, he batted .484 with 24 home runs with 66 RBI and 69 runs scored in 39 games. His 24 home runs passed Bo Jackson for second all-time in the state for home runs in a season by a high school player. In a pre-draft workout, Rasmus was clocked at 94 mph throwing from center field. He also ran 60 yards in 6.7 seconds. Rasmus helped lead Russell County to a national championship in 2005 as they finished the season ranked first in both the National High School Baseball Coaches Association poll and the USA TODAY Super 25 baseball rankings. Rasmus graduated from Russell County High School in 2005.