Cucumber (Cucumis sativus L.) is a widely cultivated plant belonging to the Cucurbitaceae family. This plant is a popular vegetable crop used in several international cuisines and traditional medicine, such as the Mediterranean diet style and Indian culture, owing to its refreshing taste, high water content, and high nutritional value. It is mainly consumed in its fresh form and is known to constitute primary metabolites such as carbohydrates, proteins, and fats. The Cucumber by-products, namely flowers, leaves, peels, seeds, and juice wastes, have recently gained scientific interest due to bioactive phytochemical classes such as phenolic compounds, flavonoids, carotenoids, and cucurbitacins. Phytochemicals are secondary metabolites produced by plants. These products are biologically active, naturally occurring chemicals in various parts of a plant, providing health benefits for humans beyond those attributed to macronutrients and micronutrients. They exhibit antioxidant, anti-inflammatory, antimicrobial, anticancer, and antidiabetic activities and have been reported to be used in the prevention and treatment of cardiovascular diseases. They further show potential in promoting skin health and improving digestive health. In addition to their potential health benefits, cucumber by-products can also be utilized in the food and cosmetic industries. There are suggestions to incorporate cucumber peel extracts into beverages and snacks for nutritional value enhancement and antioxidant activity. Cucumber seed oil, rich in essential fatty acids, can be utilized to formulate skincare products for its moisturizing and anti-aging effects. In conclusion, cucumber by-products are rich sources of bioactive phytochemicals with various health benefits. These compounds have been linked to human health by protecting against degenerative diseases. There is a research window of opportunity to explore these bioactive compounds’ full potential and develop innovative ways to utilize cucumber by-products in various applications, including functional foods and cosmetics.