Elevation of intracellular Ca²⁺ in astrocytes can influence cerebral microcirculation and modulate synaptic transmission. Recently, in vivo imaging studies identified delayed, sensory-driven Ca²⁺ oscillations in cortical astrocytes; however, the long latencies of these Ca²⁺ signals raises questions in regards to their suitability for a role in short-latency modulation of cerebral microcirculation or rapid astrocyte-to-neuron communication. Here, using in vivo two-photon Ca²⁺ imaging, we demonstrate that ∼5% of sulforhodamine 101-labeled astrocytes in the hindlimb area of the mouse primary somatosensory cortex exhibit short-latency (peak amplitude ∼0.5 s after stimulus onset), contralateral hindlimb-selective sensory-evoked Ca²⁺ signals that operate on a time scale similar to neuronal activity and correlate with the onset of the hemodynamic response as measured by intrinsic signal imaging. The kinetics of astrocyte Ca²⁺ transients were similar in rise and decay times to postsynaptic neuronal transients, but decayed more slowly than neuropil Ca²⁺ transients that presumably reflect presynaptic transients. These in vivo findings suggest that astrocytes can respond to sensory activity in a selective manner and process information on a subsecond time scale, enabling them to potentially form an active partnership with neurons for rapid regulation of microvascular tone and neuron–astrocyte network properties.