This research created a supervision model development design based on MORTIRTA coaching academics for Primary School teachers in Nalumsari District. The MORTIRTRA coaching-based academic supervision model was an academic supervision model with the MORTIRTA coaching step. MORTIRTA is an acronym for partnership, orientation, reflection, objective, identification, action plan, and responsibility. MORTIRTA coaching-based academic supervision implementation consisted of three stages. They were the plan, implementation, and follow-up. This Research & Development applied Borg & Gall design adapted from Sugiyono. The stage consisted of 1) finding potential and problems, 2) collecting the initial data, 3) designing the product, 4) validating the design, 5) revising the product, 6) testing the product, and 7) revising the product. The researchers conducted the product test at some primary schools, such as Public Elementary School No. 2 Gemiringlor, Public Elementary School 3 Ngetuk, Public Elementary School No. 1 Nalumsari, and Public Elementary School No. 1 Tunggul. These schools belonged to an experimental group. Then, the control group schools were Public Primary School No. 2 Gemiringkidul, Public Elementary School No. 3 Bendanpete, Public Elementary School No. 2 Karangnongko, and Public Elementary School No. 2 Blimbingrejo. The researchers collected the data by observing, documenting, interviewing, and distributing the questionnaire. The researchers analyzed the data descriptively and qualitatively, using N-gain and a t-test with a 0.05 significant level. The result showed MORTIRTA coaching-based academic supervision model consisted of plan, implementation, and follow-up. The aspects included creating partnership, orientation, reflection, objective, identification, action plan, and responsibility.