Estrogen receptor (ER) involvement through genomic mechanisms have been well established in different aspects of cognition and neuronal plasticity. However, much less is known about the rapid, non-genomic effects on these processes. G-protein coupled estrogen receptor (GPER) is a relatively recently discovered estrogen receptor that has previously been shown to affect learning and memory on a long term genomic timescale. This thesis investigated the rapid effects of the GPER selective agonist G-1 on four estrogen-sensitive learning paradigms: social recognition, object recognition, object placement and social transmission of food preferences (STFP) paradigm. The rapid effects of G-1 on neuronal plasticity were also examined through changes in hippocampal dendritic spine length and density. Results show that GPER activation may rapidly enhance social recognition, object recognition and object placement learning while may impair social learning in the STFP paradigm. G-1 treatment also resulted in increases of dendritic spine density in the stratum radiatum of the CA1 hippocampus. This suggests that GPER, along with the classical ERs, mediates the rapid effects of estrogen on learning and neuronal plasticity. Thus, GPER may be a viable target for enhancing cognitive function in estrogen related therapies.