The current paper examines the effect of public-private partnerships investment in energy (PPIE) on CO2 emissions while taking economic growth (GDP), foreign direct investment (FDI), and trade openness (TOP) into consideration for Bangladesh from 1997 to 2019. This paper utilizes Bayer and Hanck cointegration approach, fully modified ordinary least squares, dynamic ordinary least squares, canonical regression, and frequency domain causality technique. The outcome of this paper reveals that (i) the cointegrating association among PPIE, GDP, FDI, TOP, and CO2 emissions is verified; (ii) PPIE, GDP, and TOP affect environmental sustainability negatively; (iii) in the long term, PPIE, FDI, and TOP Granger-cause CO2 emissions in Bangladesh. This research suggests technical development for a greener production procedure and public-private partnership funding in green energy. Therefore, as a policy endorsement, this study proposes to invest in the latest technological advancements to manufacture environmentally sustainable goods via public-private partnerships.