This chapter presents the theoretical underpinnings of residential energy consumption, using diverse theoretical frameworks to provide a comprehensive understanding of consumer behavior and its influencing factors. From the perspective of consumption-related theories, the utility theory posits that residents consume energy to gain satisfaction and utility, optimizing their energy consumption mix to maximize personal utility. Consumption theory highlights that consumer behavior is influenced by income, prices, and preferences, with energy consumption being no exception, as residents adjust their consumption patterns based on their financial situation and energy price fluctuations. Among energy consumption-related theories, the Environmental Kuznets Curve theory suggests a phased relationship between residential energy consumption and economic development. Energy consumption patterns and total consumption vary across different income stages. The market failure and externality theory notes that energy markets suffer from information asymmetry and monopolies, and energy consumption generates environmental externalities, such as pollution, necessitating government intervention to correct market failures. The principal-agent theory explains the allocation of rights and responsibilities in energy consumption decisions within households and the issue of information asymmetry. The energy efficiency and rebound theory indicates that while improving energy efficiency can reduce consumption, it may also lead to a rebound in consumption due to lower usage costs, thus diminishing energy-saving effects. In terms of theories related to residential energy consumption behavior, the theory of planned behavior suggests that such behavior is influenced by behavioral attitudes, subjective norms, and perceived behavioral control, which in turn shape behavioral intentions and actual behavior. The technology acceptance model emphasizes that the acceptance of energy technologies and products by residents depends on their perceived usefulness and ease of use. The norm activation model points out that personal values, social norms, and environmental concern drive energy consumption behavior. The SOR theory explains this behavior from the perspective of stimulus-organism-response, indicating that external stimuli influence energy consumption reactions through internal psychological and physiological mechanisms of the individual.