The thalamocortical system underlies sensory perception, brain-state regulation, movement execution, and cognition. The thalamus and cortex are generated from separate sectors of the embryonic forebrain, and their reciprocal axonal projections have to grow across a complex cellular terrain through it to innervate each other. The corticofugal and thalamocortical projections start to develop synchronously at very early stages when the distances are minimal. The initial topographical organization of these axons is guided by diencephalic and telencephalic molecular gradients. Transient axonal bundles and streams of migrating cell populations then act as a guiding scaffold for these projections. Once they reach their target, the thalamocortical fibers rearrange within the transient subplate zone and later innervate the cortical plate, whereas the corticofugal axons originate from layer 5, layer 6, and subplate/layer 6b neurons and follow a specific developmental sequence as they approach the thalamus, where some of them accumulate before they enter the first -and higher-order thalamic nuclei according to their subtypes and laminar origin. Both thalamocortical and corticothalamic projections are plastic and can reshape after alterations in sensory input or various lesions. Understanding the mechanisms underlying their development and remodeling is vital to comprehending the establishment and plasticity of cortical representations.