This study, basing on the connection between close relationships and emotional experience from a socio-cognitive perspective, mainly attribution theories, aimed to examine: (1) children's attributions and emotions for their subjectively perceived positive and negative friendships with their best friend; (2) if children's attributions and emotions are differentiated depending on whether they perceive their friendship as positive or negative; and (3) the role of the attributional and intuitive (perceived quality) appraisals of the friendship in the formation of the emotions, and in the impact of the emotions on expectations about the quality of the friendship. A total of 225 children, both genders, third and fourth grades, participated in this investigation. All the participants, after writing down the name of their best friend, completed, first, the scale of emotions and, then, the scales of attributions and expectations. The results showed that the perceived positive friendships were mainly attributed to companionship-recreation and perceived help and support by the friends as well as to internal, stable, personal controllable, external uncontrollable and self-friend interactive internal factors. In contrast, the main attributions for the perceived negative friendships were non-exclusiveness, lack of companionship-recreation and friends' bad character as well as friends' controllable and internal, personally uncontrollable, external and unstable factors. Also, the participants experienced intense positive and negative emotions (particularly, friendship-and future-related) for the positive and negative friendships, respectively. Attribution (mainly, stability), compared to intuitive appraisal of friendship, was a better predictor of most of the emotions in the negative friendships group, while the pattern was reversed in the positive friendships group. Finally, emotions, attributions (not in negative friendships) and intuitive appraisal uniquely contributed into the generation of friendship expectations. Discussion of the findings focuses on enhancing children's subjective well-being and on future research.