This study asks what is the ‘best’ way to measure urban energy efficiency. There has been recent interest in identifying efficient cities so that best practices can be shared, a process known as benchmarking. Previous studies have used relatively simple metrics that provide limited insight on the complexity of urban energy efficiency and arguably fail to provide a ‘fair’ measure of urban performance. Using a data set of 198 urban UK local administrative units, three methods are compared: ratio measures, regression residuals, and data envelopment analysis. The results show that each method has its own strengths and weaknesses regarding the ease of interpretation, ability to identify outliers and provide consistent rankings. Efficient areas are diverse but are notably found in low income areas of large conurbations such as London, whereas industrial areas are consistently ranked as inefficient. The results highlight the shortcomings of the underlying production-based energy accounts. Ideally urban energy efficiency benchmarks would be built on consumption-based accounts, but interim recommendations are made regarding the use of efficiency measures that improve upon current practice and facilitate wider conversations about what it means for a specific city to be energy-efficient within an interconnected economy.