Antioxidants are important structures that protect the body from various diseases by clearing the free radicals accumulated in the human body. There are many antioxidants in the body like enzymes, hormones, and proteins. Apart from these, there are many antioxidant substances such as vitamins, tannins, phenolic acids, flavonoids, which are naturally found in many foods. Hazelnuts are one of the foods that contain antioxidants. It is a plant that grows in abundance in our country and contributes to the country’s economy. During the hazelnut harvest and processing, it also occurs by-products such as husk, shell, and skin and there is not much economic contribution from these products. This study was carried out to show that hazelnut husks which are a by-product of hazelnut also have high antioxidant properties and can be used in different fields in the industry to contribute to the economy. For this purpose, husks of the plump hazelnut (Corylus avellana L.) species grown in Bartın were freshly collected and extracted with different solvents such as water, water-acetone, acetone, and ethanol. The obtained extract of total phenolics and flavonoid amount, DPPH free radical scavenging activity, ABTS cation radical removal activity, and copper (II) reducing the determination of antioxidant capacity (CUPRAC) were measured. When the results were examined, it was seen that hazelnut husks had high antioxidant properties. In addition, the total phenolic amount (273.56 ± 10.12 mg / g extract), DPPH (18.74 ± 0.87 µg / ml), ABTS (4.78 ± 0.56 µg / ml) and CUPRAC (8.74 ± 2.13 µg / ml) activities of water-acetone extract compared to other extracts has been determined to give the best results.