The increasing adoption of rooftop photovoltaic (PV) systems, electric vehicles (EVs), and electric heating positions the residential sector as a key provider of demand-side flexibility to support a sustainable energy transition. Demand response (DR) enables households to adjust electricity use to help balance the grid, but effective implementation relies on understanding how consumers decide to participate. This doctoral dissertation investigates residential consumers’ decision-making regarding DR enrollment. The research identifies motivators across different socioeconomic groups, quantifies willingness to provide flexible loads, examines variations among household types, and models decision-making behavior mathematically. A detailed survey of Finnish households was conducted to assess motivations and preferences. The findings informed the development of an agent-based model that simulates how enrollment evolves over time. The study also proposes a pricing strategy for aggregators to attract residential flexibility cost-effectively. Results highlight that motivators such as financial savings, environmental awareness, and convenience significantly influence participation, and that willingness varies by demographic factors. These insights support DR service providers, policymakers, and researchers in designing more effective DR programs. By linking behavioral factors with system-level flexibility goals, this work offers practical guidance to maximize residential DR participation, ultimately contributing to a more resilient and decarbonized energy system.