Many genetic factors interact in the regulation of the hippocampus, a complex network of brain regions that play important roles in cognitive functions, spatial navigation, emotional control, and social interaction. This chapter reviews the neuronal genetics of various aspects regarding the hippocampus, from the heterogeneous gene expression in the hippocampal anatomy to the genes essential for the development of the hippocampus like Paired Box 6 (PAX6) and LIM Homeobox 2 (LHX2). Moreover, it presents insights into various domains of hippocampal function, including cognitive processes, such as memory and learning, spatial navigation, and emotional regulation, elucidating the neural genetics underpinning its diverse functions. Furthermore, this chapter discusses the participation of genes, such as immediate early genes like Fos proto-oncogene (c-FOS), and activity regulated cytoskeleton-associated protein (ARC), cAMP response element-binding protein (CREB), and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), in neuroplasticity and memory consolidation. It shows how they can be related to cognitive processes. It will also explore the heterogeneous gene expression in spatial navigation and spotlighting genes, such as nuclear receptor 4 (NR4A), period circadian regulator 1 (PER1), and Dual specificity phosphatase 5 (DUSP5), that influence processes such as neurogenesis and synaptic plasticity. Furthermore, it investigates the effects of gene expression on emotional control and social behavior, including the role of brain-derived neurotrophic factor (BDNF), serotonin, and dopamine receptors in mood disorders and stress responses, further delineating the impact of the hypothalamic–pituitary–adrenal (HPA) axis and inflammation on hippocampal activity that may suggest novel antidepressive interventions. Overall, it aims to underline the genetic regulation of processes in which the hippocampus is involved.