Assessment of energy and environmental issues has received a special focus due to global warming and climate vulnerabilities. Energy, environment and economic development simultaneously yielded a combined effect, which is favorable from the economic point of view while unfavorable for environmental aspects. It is necessary to measure the energy, economic and environmental performance with appropriate methods. Therefore, this study measures the energy security and environmental efficiency. Data used in this study were collected from the official website of International Energy Agency (IEA), British Petroleum (BP) and World Bank. We employ a non-radial DEA technology for assessing energy and environmental efficiency for OECD countries. Results reveal that the values of energy intensity range from 0.93 to 0.30, while GHG emission per capita values range from 24.61 to 5.28. As far as energy efficiency is concerned, Iceland and Greece have the highest value (0.99) of energy efficiency, whereas Ireland has the lowest value (0.34) of energy efficiency. Further analysis shows that Austria, Australia, Portugal and Spain have values between 0.70 and 0.80 for energy intensity, whereas UK, Sweden, Germany and the USA have values of energy intensity, between 0.40 and 0.50. The study proposes some valuable policy implications for policy and decision-makers to make the environment more sustainable.