Apricot (Prunus armeniaca L.) leaves were studied to assess the potential of apricot leaves for future studies and their applications in nutraceutical and bioactive functional ingredients. The changes in the phenolic profile, carotenoids, pigments and antioxidant potential were studied at four maturation stages. Polyphenols and carotenoids were studied using reversed-phase HPLC-DAD. Pigments, total phenolic contents and radical scavenging activity were also measured. Results revealed twelve phenolic compounds in the apricot leaves. The major phenolic compounds were 3-O-caffeoylquinic acid (14.6–49.6 mg/g), 4-O-caffeoylquinic acid (0.56–7.5 mg/g), 5-O-caffeoylquinic acid (5.6–25.7 mg/g) and quercetin-3-O-glucosides (8.6–19.9 mg/g), while others include caffeic acid and derivatives of coumaric acid and kaempferol. Significant changes were observed in polyphenolic compounds during maturation. Lutein (56.7–65.7 µg/g), neoxanthin (0.66–4.79 µg/g), 5,6-epoxy-α-carotene (5.89–7.9 µg/g), and β-carotene (12.3–26.9 µg/g) were the major carotenoids. There were significant variations in the carotenoids, pigment contents, total phenolic contents and radical scavenging activity during maturation. In conclusion, significant variation occurred in the polyphenolic profile, carotenoids contents and antioxidant potential of apricot leaves under the studied conditions.