The objective of this study was to understand the Gasoline Particulate Filter (GPF) filtration process and examine the effects of GPF parameters like wall thickness, porosity, Mean Pore Size (MPS) and length on the filtration efficiency (FE). It also aimed to investigate the implications of installing a GPF on a Gasoline Direct Injection (GDI) engine. Four filters were tested first on a bench setup with a soot generator as source for the particle emissions and then installed on a GDI engine on a dynamometer where the overall emissions and filtration efficiencies were investigated. Soot concentrations, particle number emissions and gaseous emissions were measured. Particle morphology and soot deposition were analyzed using a Transmission Electron Microscope (TEM) and a Scanning Electron Microscope (SEM). Results showed an increasing filtration efficiency with increasing soot deposition. Results also showed a greater effect of MPS on filtration efficiency than wall thickness and filter length.