The present disclosure relates to RNAi agents, e.g., double stranded RNAi agents, capable of inhibiting Apolipoprotein C-III (also called APOC3, apoC-III, APOC-III, and APO C-III) gene expression, and compositions that include APOC3 RNAi agents. The APOC3 RNAi agents disclosed herein may be conjugated to targeting ligands, including ligands that include N-acetyl-galactosamine, to facilitate the delivery to cells, including to hepatocytes. Pharmaceutical compositions that include one or more APOC3 RNAi agents, optionally with one or more additional therapeutics, are also described. Delivery of the APOC3 RNAi agents in vivo provides for inhibition of APOC3 gene expression, and can result in lower triglycerides and/or cholesterol levels in the subject. The APOC3 RNAi agents can be used in methods of treatment of APOC3-related diseases and disorders, including hypertriglyceridemia, cardiovascular disease, and other metabolic-related disorders and diseases.