Organizations are spending large amounts of money on their energy consumption. The scarcity of energy resources, along with their price volatility, has become a major concern for all industries. Consequently, the need for managing and conserving energy has recently gained larger attention. A good management always pursues savings opportunities with minimum investments; hence, establishing an energy management system can provide the right approach to detect opportunities and sustain improvements. This article proposes the Lean Six Sigma energy management model (LSS_EnMS) based on the framework of International Organization for Standardization (ISO) 50001 for energy management, supported by the LSS approach define, measure, analyse, improve and control (DMAIC). The LSS_EnMS model applies the DMAIC approach to the energy management process in companies and incorporates the needed tools to define system requirements, analyse energy data, establish a systematic approach to identify energy opportunities and finally to guarantee sustainable system improvements. The model has shown the compatibility of Six Sigma approach with the ISO 50001 framework and has provided guidelines for effective system implementation. A prominent pharmaceutical company in Jordan was taken as a case study to show the significance of this model, and how this approach can lead to valuable and advantageous results in terms of real case application.