List of Houston Astros minor league affiliates

The Houston Astros farm system consists of seven Minor League Baseball affiliates across the United States and in the Dominican Republic. Six teams are owned by the major league club, while the Asheville Tourists are independently owned.

The Astros have been affiliated with the Double-A Corpus Christi Hooks of the Texas League since 2005, making it the longest-running active affiliation in the organization. The longest continuous affiliation in team history was the 21-year relationship with the Double-A Southern League's Columbus Astros/Mudcats from 1970 to 1990. Their newest affiliates are the Triple-A Sugar Land Space Cowboys of the Pacific Coast League and the High-A Asheville Tourists of the South Atlantic League, which became Astros affiliates in 2021.

Geographically, Houston's closest domestic affiliate is the Sugar Land Space Cowboys, which are approximately 20 mi away. Houston's furthest domestic affiliate is the Single-A Fayetteville Woodpeckers of the Carolina League some 1165 mi away.

Current affiliates
The Houston Astros farm system consists of seven minor league affiliates.

1962
Minor League Baseball operated with six classes (Triple-A, Double-A, Class A, Class B, Class C, and Class D) in 1962.

1963–1989
Prior to the 1963 season, Major League Baseball (MLB) initiated a reorganization of Minor League Baseball that resulted in a reduction from six classes to four (Triple-A, Double-A, Class A, and Rookie) in response to the general decline of the minors throughout the 1950s and early-1960s when leagues and teams folded due to shrinking attendance caused by baseball fans' preference for staying at home to watch MLB games on television. The only change made within the next 27 years was Class A being subdivided for the first time to form Class A Short Season in 1966.

1990–2020
Minor League Baseball operated with six classes from 1990 to 2020. In 1990, the Class A level was subdivided for a second time with the creation of Class A-Advanced. The Rookie level consisted of domestic and foreign circuits.

2021–present
The current structure of Minor League Baseball is the result of an overall contraction of the system beginning with the 2021 season. Class A was reduced to two levels: High-A and Low-A. Low-A was reclassified as Single-A in 2022.