Prosocial behaviors are first observed at an early age. However, almost no studies examine different prosocial behaviors together or provide an intervention-free observation. Therefore, in this study, preschool children’s helping, sharing, cooperation, informing, comforting, and compliant prosocial behaviors were investigated in their kindergarten context by using naturalistic observation. Another aim was to observe prosocial behavior not specified in the literature. The study comprised 16 children aged 13–23 months, 30 children aged 24–35 months, 28 children aged 36–47 months, 32 children aged 48–59 months, and 35 children aged 60–70 months; thus, 141 children (62 girls, 79 boys) were observed. Observations were conducted during the children’s activity, free play, and structured play timeframes, and behaviors were recorded by the observer. The total duration of observations conducted for each age group in multiple sessions was 500 minutes. The frequencies of prosocial behaviors were examined in each age group. Data indicated that helping, sharing, comforting, and compliant prosocial behaviors were observed after the children’s first birthday. Cooperation and informing behaviors were observed during the second year of the children’s life. In addition to these prosocial behaviors, some behaviors such as defending and motivating others, which both contribute to the well-being of others, were also observed in this study, and related prototypes were presented in the results section. Additionally, in-class practices, peers’ past experiences with each other, and characteristics of children (whether they are agents or recipients of prosocial behavior) influenced the emergence of different prosocial behaviors. Results, which further enhanced the sets of evidence pointing to the multidimensional nature of prosocial behaviors, were discussed in the context of classroom observations conducted on preschool children.