Vector boson scattering (VBS) is a rare process in the electroweak sector of the Standard Model, and is of interest to study at the Large Hadron Collider because of its relationship with electroweak symmetry breaking. This seminar introduces the VBS process in the context of the Standard Model, summarizes the mathematical techniques used to extract its small signals, and present a measurement of its fiducial cross-section in semileptonic final states.