With the advent of legalization and increased availability of cannabis products, rates of cannabis use are on the rise, including in pregnant individuals. Often used to alleviate nausea and pain, although many believe that use of cannabis during pregnancy is harmless, a significant body of literature indicates the prenatal use is associated with molecular, morphological, and behavioral changes in the juvenile and adolescent offspring. Despite these studies, debates remain as to the causal impact of cannabis on these outcomes. Preclinical models have been essential tools in determining the direct impact of in utero cannabinoid exposure on the fetal environment, brain development, and behavior during these early critical periods. Neuroplasticity and the emergence of social and affective behaviors from infancy to adolescence set the foundation for healthy development and are vulnerable to prenatal drug exposure. This chapter describes the known effects of in utero cannabinoid exposure on the placenta and fetal development garnered by preclinical studies and how these changes relate to behavioral phenotypes observed early in life.