<p>Environmental exposure to lead (Pb) and cannabis use are two of the largest public health issues facing modern society in the United States and around the world. Exposure to Pb in early life has been unequivocally shown to have negative impacts on development, and recent research is mounting showing that it may also predispose individuals for risk of developing substance use disorders (SUD). At the same time, societal and legal attitudes towards cannabis (main psychoactive component delta-9-tetrahydrocannabinol) have been shifting, and many American states have legalized the recreational use of cannabis. It is also the 3^rdmost widely used drug of abuse in the US, and rates of cannabis use disorder are on the rise. This thesis sets out to establish whether there is a link between early life Pbexposure and later THC-related behavior in C57BL6/J mice, as has been demonstrated for other drugs of abuse. The first aim seeks to answer whether Pbexposure affects physiological THC sensitivity (as measured by the cannabinoid-induced tetrad). The secondaimseeks to answer whether Pbexposure affects edible THC self-administration and the development of THC tolerance (also measured by the tetrad).It was hypothesized that Pbexposure would decrease THC sensitivity (Aim 1), would enhance THC self-administration (Aim 2), enhance the development of THC tolerance (Aim 2), and finally that sex-dependent effects of Pb-exposure and THC would be observed (Aims 1 & 2). These hypotheses ended up not being supported, but Aim 1 produced findings indicating that THC sensitivity was increased by Pbexposure, but only in female mice. Future researchwill hopefully be able to fully explore the implications of these findings.</p>