The relationship among morphologically different forms of smiling and laughter was examined. The participants were 19 Brazilian preschool children. Each child was observed a total of 60 min. in three 10-min. sessions on the playground and three 10-min. sessions in the classroom. Analysis suggests that the various forms of smiling do not simply express different intensities of a single emotion. A two-dimensional structure was indicated by factorial analysis. The first dimension, which could be called playfulness-mock aggression, consisted of a broad smile and laughter. The second dimension, which could be called friendliness-appeasement, consisted of a closed and upper smile. The pattern of correlation found between expressive behaviors and both teacher's and peers' evaluations gives further support to the interpretation that smiling is an heterogeneous category.