Head-mounted miniaturized two-photon microscopes enable cellular-resolution recording of neural activity deep in the mouse brain during unrestrained behavior. Two-photon microscopy, however, is traditionally limited in frame rate by the necessity of scanning the excitation beam over a large field-of-view (FOV). Here, we present two types of multiplexed miniaturized two-photon microscopes (M-MINI2Ps) that preserve spatial resolution while increasing frame rate by simultaneously imaging two FOVs and demixing them temporally or computationally. We demonstrate large-scale (500 × 500 μm FOV) multiplane calcium imaging in visual and prefrontal cortices of freely moving mice during spontaneous exploration, social behavior, and auditory stimulus. The increased speed of M-MINI2Ps also enables two-photon voltage imaging at 400 Hz over a 380 × 150 μm FOV in freely moving mice. With compact footprints and compatibility with the open-source MINI2P, M-MINI2Ps enable high-speed recording of rapid neural dynamics and large-volume population activity in freely moving mice, providing a powerful tool for systems neuroscience.