This study explores how the form and behavioural anthropomorphism of avatars affect user satisfaction through cognitive, affective, and social responses. Whilst extant research has heretofore treated anthropomorphism in a unifying fashion, this study differentiates it into two distinct dimensions: form anthropomorphism and behavioural anthropomorphism. Utilising social response theory as a framework, the study hypothesises that perceived personalisation, entertainment, and informativeness mediate the relationship between these two types of anthropomorphism and user satisfaction. Additionally, the study explores the moderating effect of user openness. The Structural Equation Model (SEM) and the analyses of mediation and moderation demonstrate that both form and behavioural anthropomorphism have a positive effect on user satisfaction, with openness moderating the effect of form anthropomorphism. The findings contribute to the extant literature by clarifying the different impacts of form and behavioural anthropomorphism, emphasising the role of individual traits, and offering practical insights for avatar design in enhancing user satisfaction.