Import product diversification is a major parameter in international trade. Import diversification contributes to economic growth and affects the environment due to its impact on energy consumption. In this article, we investigate the impact of import product diversification along with income, oil prices, natural resources, population, and foreign direct investment on energy demand, covering a composite sample of 102 developing and 36 developed economies over the period from 1995 to 2020. We also assess the impact of import diversification on energy demand considering all sub-samples. We find a significant long-run cointegration between total energy demand and import diversification for both developed and developing countries, confirmed by Pedroni cointegration tests. We further denote that import diversification together with other independent variables is stationary after the first differences in LLC unit root tests. Contrary to traditional methods, we apply panel quantile regression and conclude that import diversification, GDP, oil prices, foreign direct investment, natural resources, and population share long-run integration with total energy consumption for both developed and developing countries. The Dumitrescu and Hurlin short-run causality test confirms the existence of pair-wise bidirectional causality between all independent variables including import diversification, GDP, oil prices, natural resources, foreign investment, and population with energy demand. Our empirics conclude with important policy implications for sustainability.