This research is a qualitative research that aims to explain, understand, and obtain a profound picture of "the causes of" selective elective mutism "class II and V students in Karanglo Elementary School", The research method used in this study is a case study, aiming to examine the cases that occur in students who experience Selective Elective Mutism disorders. Data collection techniques use in depth interviews and use non participatory observation. Data analysis using qualitative data analysis according to Miles and Huberman with steps: data reduction (data reduction), data presentation (data display), and conclusions then verified (conclusion drawing /verification). From the results of the acquisition of data that has been reduced and presented through an interview and observation process with strong evidence supporting data or information relating to Selective Elective Mutism disorders, the data obtained will be more reliable. The results show that selective causes of elective mutism in children are: due to family, environmental, and genetic factors or heredity.