Hyperoxaluria is categorized as either primary (PH), enteric (EH), or idiopathic (IH). The PHs are a group of ultra-rare genetic disorders resulting in oxalate overproduction that can result in end-stage renal disease (ESRD). Novel RNA inhibitory drugs are now available to treat PH that significantly reduced the risk of kidney stones. EH is driven by fat malabsorption and enhanced intestinal oxalate absorption, which in severe cases can result in ESRD. Therapies for EH are limited and research is focused on novel strategies to reduce intestinal oxalate absorptions. Causes for IH are unclear and may involve multiple mechanisms.