The mammal brain must dynamically and rapidly adapt to the ever-changing sensory environment. Despite the known importance of neural plasticity in cellular processing, we only have a limited understanding of how this is achieved in vivo. Here, we performed whole-cell patch clamp electrophysiology from layer 2/3 pyramidal neurons in the primary somatosensory cortex in vivo to investigate whether sensory information is dynamically encoded in cortical neurons. First, the plasticity of sensory encoding was tested by repetitive tactile stimulation delivered to the forepaw. Here, sensory encoding was plastic, leading to an increase in the sensory-evoked voltage response. Intracellular application of MK801 illustrated this plasticity was NMDA-dependent. To test whether plasticity of sensory encoding also occurs following sensory-based learning, voltage responses were recorded from mice following learning of a tactile-association task. Here, mice were trained to receive a reward in response to tactile stimulation delivered to the forepaw. Compared with novice mice, the tactile-evoked voltage responses in the awake state were on average changed throughout learning. Taken together, these findings illustrate that sensory encoding is dynamic and can undergo plasticity following repetitive sensory stimulation and sensory-based learning.