The purpose of the study was to explore the negative emotions experienced by elementary school children in physical education class. Grounded theory was employed to find out the causes of the negative emotional experiences. Twenty two boys and girls participated in the study. Semi-structured interview, participant observation, and emotional diary written by the participants for 4 months, were employed. As a result, 85 concepts, 28 subcategories, and 15 categories were derived from the raw data. Through axial coding, the relationships among the 15 categories were identified. The conditions that caused negative emotional experiences were ‘interfering with peer activity’, ‘complaining about peer behavior’ and ‘negative verbal accusation’in core category. The nature of physical education class which emphasizes competition and cooperation was a reason that students experienced negative emotions in contextual condition. ‘Being aware of surroundings’, ‘impulse to do something’, ‘social relationships’, ‘being aware of activity levels’ worked as mediating categories. Action/reaction strategies were ‘active and passive coping measures’. As a consequence, ‘negative perception toward class and peers’, ‘releasing unpleasant emotions’, ‘fortified effort to solve problems’ categories emerged. The negative emotional experiences in physical education class might be called as the process of frustration and overcoming from negative emotional experiences.