Neurons exhibit selectivity for specific features: a property essential for extracting and encoding relevant information in the environment. This feature selectivity is thought to be modifiable by experience at the level of the cortex. Here, we demonstrate that selective exposure to a feature during development can alter the population representation of that feature in the primary visual thalamus. This thalamic plasticity is not due to changes in corticothalamic inputs and is blocked in mutant mice that exhibit deficits in retinogeniculate refinement, suggesting that plasticity is a direct result of changes in feedforward connectivity. Notably, experience-dependent changes in thalamic feature selectivity also occur in adult animals, although these changes are transient, unlike in juvenile animals, where they are long lasting. These results reveal an unexpected degree of plasticity in the visual thalamus and show that salient environmental features can be encoded in thalamic circuits during a discrete developmental window.