Quercetin contains antioxidant compounds that are proven to reduce the level of low-density lipoprotein (LDL) and increase high-density lipoprotein (HDL). The challenges of poor solubility and bioavailability demand the modification of quercetin in the form of Self Nanoemulsifying Drug Delivery System (SNEDDS). This study aims to develop a SNEDDS formulation of quercetin compound with a combination of Pangasius hypophthalmus offal fat extract oil as a hypercholesterolemia drug using the Box-Behnken Design. Dry rendering extraction of Pangasius hypophthalmus fish offal fat produced pure fish oil with GC-FID results containing omega 3 (1.33%), omega 6 (1.48%), and omega 9 (8.20%). SNEDDS was developed using the Box-Behnken Design method with variations of 85% tween 80, 10% propylene glycol, and 5% Pangasius hypophthalmus oil. The optimum formula was determined based on droplet size, emulsification time, and % transmittance parameters using Stat-Ease® 360 Design Expert software. The optimum formulation exhibited a droplet size of 22.6 ± 0.11 nm with a polydispersity index of 0.641 ± 0.02 and a zeta potential value of -11.6 ± 0.51 mV. In vitro testing showed quercetin SNEDDS could quickly form spontaneous nanoemulsions when in contact with water compared to quercetin not in the form of SNEDDS, with a Q30 obtained of 91.2889%. The depiction of the drug release profile at 30 minutes can also be referred to as the Q30. The SNEDDS dissolution profile has requirements, namely that it must dissolve within 30 minutes minimum 80%. In vivo testing showed quercetin SNEDDS had antihypercholesterolemia activity by reducing cholesterol levels by 51.5%, thus providing greater effectiveness in reducing cholesterol levels than SNEDDS without quercetin and preparations not in the form of SNEDDS.