Locomotion is a complex motor behavior needed by animals and humans to move through the environment. All forms of locomotion, including swimming, flying, walking, running, and hopping, are repetitive motor activities that require the activation of the limb and body muscles in an organized rhythm and pattern. Locomotion is regulated by several different neuronal systems in the brain and spinal cord. The behavior is selected by the basal ganglia and initiated by the mesencephalic locomotor region in the midbrain via the reticulospinal neurons in the lower brainstem. This leads to the activation of the locomotor networks, called central pattern generators, in the spinal cord which produce the rhythm and pattern of locomotion and convey it to the muscles. Locomotion is further regulated by feedback from skin and muscle afferents and neuromodulatory systems which act on the central pattern generator. Cerebellar and cortical motor circuits allow for the adjustment of ongoing locomotion based on information from the movements themselves and the sensory systems. This chapter will summarize these different regulatory neuronal components involved in the control of locomotion.