Currently, flaxseed oil is used as an important functional food constituent owing to its large content of omega-3 fatty acids. However, flaxseed oil does not contain carotenoids that could enhance the oxidative stability of the oil. In this study, carotenoids extracted from sea buckthorn pomace were used to enrich cold-pressed flaxseed oil via an ultrasound-assisted extraction technique (UAE). The process parameters were optimized through Box-Behnken design to maximize the carotenoid content in the flaxseed oil. The results obtained by statistical analysis indicated that the yield of 14.02 mg/L of carotenoid content was found in the enriched flaxseed oil at 75.6 min, feed to oil ratio of 19.9 (wt. basis), and amplitude 80.81%. Further, UAE at optimum process parameters was compared with the conventional extraction (CE) method, and it was found that UAE had ~ 49 wt% of higher carotenoid content relative to CE. The physicochemical properties of the enriched flaxseed oil were determined to evaluate the effects of carotenoid enrichment in the flaxseed oil. Based on the outcomes of the present investigation, enriched flaxseed oil could be the potential source for the pharmaceuticals and nutraceuticals industry.