The present invention provides compositions comprising therapeutic nucleic acids such as interfering RNA that target apolipoprotein C-III (APOC3) gene expression, lipid particles comprising one or more (e.g., a cocktail) of the therapeutic nucleic acids, methods of making the lipid particles, and methods of delivering and/or administering the lipid particles (e.g., for the treatment of lipid diseases or disorders such as atherosclerosis or a dyslipidemia such as hypertriglyceridemia or hypercholesterolemia).