Shifting from fossil-fuel (FF) to renewable energy systems, a process known as energy transition (ET), is crucial for developing countries as the ET brings new opportunities to accomplish leapfrog development for achieving carbon neutrality. Parallel to climate change, developing countries face energy security and independence issues with extra pressures such as the Covid-19 pandemic and increasing inequality. Taking Mexico as a case, four ET scenarios under “gradual” or “rapid” narratives are developed with the Kaya Identity. Gradual Transition Scenarios (GTS) present a business-as-usual scenario with natural gas as the most significant fuel in the supply mix due to economic and social concerns. Rapid Transition Scenarios (RTS) propose a combination of FF and renewables or a full deployment of Renewable Energy Sources (RES). The results show that GTS reach 491∼ 501 Mt CO2 emissions in 2050, risking a carbon lock-in, stranded assets and economic losses. RTS reach 87∼103 Mt CO2 in 2050 with RES prioritization, energy efficiency improvements and coal phase-out. In particular, following GTS would mean failing to join global efforts to limit warming temperature to 1.5 °C. Alternatively, following RTS brings Mexico closer to achieve carbon neutrality. Several strategies are proposed, including reducing the carbon intensity of the energy supply mix, increasing energy efficiency, prioritizing environmental protection, improving actions based on science, and promoting environmental education and awareness. This paper presents a consistent methodology to encourage ET in developing countries where the role of science is still not fully exploited under the goal of carbon neutrality.