Tropidonophis mcdowelli, the northern New Guinea keelback, is a species of colubrid snake. It is found in northern New Guinea in both Papua New Guinea and Western New Guinea. Its specific name honors Samuel B. McDowell, American herpetologist (1928–2014).
Tropidonophis mcdowelli occurs in lowland and montane rainforest at elevations of NaNm (-2,147,483,648feet) above sea level in association with watercourses.