Reducing the energy consumption of manufacturing processes and machine tools can considerably affect the environmental and economic impact of industrial activities. Since the 2008 global financial crisis, many scholars have focused on modeling the energy consumption of basic machining processes such as turning, milling or grinding, etc., and investigated the consumption characteristics of related machine tools. At the same time, various industries have increased their use of more complex and hybrid machine tool systems such as turn-mill machines; these advanced systems have part and operation flexibility and can be set up in a relatively short amount of time. As the complexity of these typically high-precision machining systems increases, understanding their energy consumption characteristics becomes more difficult. This study aimed to develop a generic energy model for turn-mill machine tools and related processes in order to predict the energy consumption of complex parts with both turn and mill features. The generic prediction model is adapted to a high precision, high-end turn-mill machine tool and further verified by two case studies. The results of the first case study revealed that the energy estimation model developed in this study had a 95% accuracy in estimating the energy consumption of a workpiece with both milling and turning features. The second case study investigated energy consumption of orthogonal turn-milling process with a high material removal rate (MRR), first time in literature. The results of this second case study indicate that even though the power requirements of turn-milling are higher than conventional rough cut turning, the high MRR results in a lower total energy consumed per feature.