This study seeks to recognize teachers’ lived experiences about teaching-learning process in multi-grade classes. The approach of the study is qualitative under the rubric of phenomenological studies. The statistical population consisted of the teachers of multi-grade classes in a non-prosperous province and a prosperous one. 14 teachers were selected using criterion sampling technique for an interview. The interviews were recorded and transcribed with the interviewees’ permission; and they were analyzed using Creswell data analysis. In order to evaluate the validity of the questions, the viewpoints of experts in the field of educational sciences as well as some teachers experienced in multi-grade classes were taken into account. The reliability was approved through examination by the participants and asking from counterparts. The results showed that teachers of multi-grade classes in both provinces had similar views on using teaching methods, determining learning activities and grouping methods. However, they did not have the same views on determining the type of learning materials and resources. The results show that in multi-grade classes various teaching methods such as peer teaching and integrated teaching, leading resources and materials such as the local community, nature, and discarded materials and objects, different grouping methods such as adjacent grouping, row grouping, and sex grouping, and finally various learning activities including self learning and peer learning are utilized. Multi-grade teachers in the two provinces have similar viewpoints regarding teaching methods, learning activities, and grouping methods, but are of different viewpoints on kinds of learning materials and resources.