Maize originated in Mexico, and its closest wild relatives are other subspecies of teosintes that belong to the same species as maize (i.e., Zea mays), among which two subspecies are associated with the origin of modern maize. Slightly more distantly related to maize are other teosinte species within the same genus as Zea mays. Even more distantly related are species of the genus Tripsacum. All of these serve as important sources of gene resources for maize breeding. Based on an overview of the classification and geographical distribution of maize wild relatives, this article describes the status of in situ and ex situ conservation of global germplasm resources of maize wild relatives, evaluates their utilization value in maize breeding, and reviews the history and current status of germplasm enhancement and breeding use based on these wild relatives. Finally, key directions and technical approaches are proposed for future utilization in maize breeding.