Phytochemicals are vital bioactive compounds found in plants, known for their health benefits including antioxidant properties. This study compared the phytochemical composition and antioxidant potential of Irish potato tubers, unripe plantain, and pawpaw fruits. Freshly harvested Irish potato tubers, unripe plantain, and pawpaw fruits were bought from Aba Grocery Market, Nigeria. The samples were identified and authenticated. After preparation and drying, the samples were ground into fine powders. Phytochemical analysis was conducted using HPLC method for estimation of phenol profile, standard methods for determination of total flavonoid and phenol content in plant samples were used. The capacity to scavenge free radicals and antioxidant activities were assessed using standard assays. The phenolic profile of the plant samples revealed the presence of many phenolic compounds. The total phenolic and flavonoid contents were highest in Irish potatoes (3.61 mg/ml and 9.29 mg/dl, respectively). The antioxidant assays revealed that Irish potatoes exhibited the highest total antioxidant capacity and free radical scavenging potential, followed by unripe plantain and pawpaw fruits. The study confirms that Irish potato tubers have the highest antioxidant and free radical scavenging potential compared to unripe plantain, and pawpaw fruits. Unripe plantain and pawpaw fruits are also rich in phytochemicals with significant antioxidant properties. These findings suggest their potential use in nutraceuticals and functional foods to promote health and prevent oxidative stress-related diseases.