This chapter relates the neurobiology of olfactory processing to social functioning in humans, with a focus on schizophrenia to highlight the understanding of compromise of these processes. Olfaction may be a sensory modality that evolved early in order to process social information. This sensory modality is comprised of two intricately interwoven olfactory systems in mammals, the accessory and main olfactory systems. Both olfactory systems may also be relevant to social affiliation and reproduction, including through pheromones. Olfactory regions and the hypothalamus are central to the circuitry of human emotions. Motivated behaviour is intertwined with olfactory processing through overlap in neural circuitry, including the limbic system, temporal and frontal lobes, and thalamus. Motivational aspects of odours arise from the hypothalamus, deriving from input from the amygdala and midbrain. Odour identification deficits are robustly described in schizophrenia. Social deficits represent a significant component of disease expression in schizophrenia.