Despite its wide use in marketing research, flow still lacks a proper conceptualization. Building on analytical procedures and two studies, this paper offers a conceptualization that regards flow as the process from engrossment to enjoyment. In so doing, formerly declared flow dimensions (e.g., challenge-skill balance, clear goals) are identified as antecedents to the flow process. An important implication of this distinction is that the core flow process can also exist in reactive consumption experiences, such as listening to music or watching TV. Hence, the research has important implications for both marketing research and practice.