An oil separator-muffler for a compressor includes an inner chamber with an oil accumulation region and a wall positioned in the inner chamber. The wall defines a separator region and has an impingement surface. The arrangement of the wall in the inner chamber defines flow channels of varying cross-sectional areas. A mixture inlet for the separator-muffler provides a passageway for an oil gaseous refrigerant mixture to flow from the exterior of the separator-muffler into the separator region. The oil is separated from the mixture as the mixture impinges against the impingement surface and flows into the oil accumulation region. A channel in fluid communication with the oil accumulation region provides a passageway for the separated oil from the accumulation region to the exterior of the separator-muffler. The separated gaseous refrigerant flows from the separator region and through the flow channels of varying cross-sectional areas, thereby inducing a noise reduction mechanism, and a gas outlet provides a passageway for the separated gaseous refrigerant to exit the separator-muffler.