Mutual assistance is viewed from an educational perspective as a unique opportunity for mixed-age learning. However, there is currently little empirical research to support this assumption. The present study investigates how elementary school children help each other in class and to what extent this assistance can be beneficial for learning. Over a period of two years, help processes among children in five mixed-age classes were documented and analyzed. Teachers were interviewed about their concepts of mutual assistance. The results reveal a diverse range of help processes among elementary school children and open up development opportunities for mixed-age teaching.