At just 16 years, Nii Lamptey scored on his senior debut International for Ghana in a 1992 African Cup of Nations Qualifying home match against Togo in the 43rd minute. Ghana won the match 2–0. He became a regular International and his superb performances earned him a starting spot in the "Black Stars", forming a potent attacking force together with team captain Abedi Pele and Super striker Tony Yeboah. Ghana lost the final of the 1992 African Cup of Nations to Côte d'Ivoire on a marathon penalty shoot-out in Senegal, a game the mercurial Lamptey started at just 17 years. He continued to blossom at senior International level at such a young age, playing any and every Ghana International game since then.