The purpose of this study was to determine the role of the principal's interpersonal communication on the work motivation of teachers in Public High School 1 Merapi Barat. The research method used is descriptive qualitative which is specific to describing, then first of all the author will describe what the results obtained at the research location in this case are the role of the principal's interpersonal communication on the work motivation of teachers in Public High School 1 Merapi Barat. Interpersonal communication aims to convey everything about the contents of his thoughts and feelings to the communicant. The expression of the contents and thoughts and feelings if applied correctly with the right ethics will be able to prevent and avoid conflicts between individuals, between groups and even between nations so as to maintain national unity and integrity. From the analysis of this research, a leader is required to be able to communicate effectively interpersonal in order to be able to have emotional closeness between leaders and subordinates and fellow subordinates so that when the delivery of information takes place it will be easier and more relaxed in achieving the goals of information, the closeness that is owned makes the information. what is delivered is easy to accept and run. Where later these factors can increase and play a role in teacher motivation.