The main purpose of this study was to assess the validity of Grade 10 Math Model Exams byrnconsidering some selected secondary schools in Oromia Regional State. Thus, evidences on therncontent validity and criterion related validity of these exams were gathered and analyzed. In thernstudy, mixed-methods research design was employed. The necessary data were collected fromrnthe selected secondary schools by using interview, questionnaire, check-list and documentrnanalysis. Questionnaire was administered to 31 teachers currently teach Grade 10 mathematics.rnMoreover, booklets of Grade 10 Math Model Exams were gathered from the schools andrnevaluated for appropriateness, relevance and representativeness of the items that were sampledrnby these exams. By using systematic sampling scores of 230 students on Grade 10 and 12 MathrnModel Exams, EGSECE and EUEE were also collected and analyzed. The criterion relatedrnvalidity evidences of Grade 10 Math Model Exams were analyzed through correlation andrnmultiple regression analysis accordingly. The findings indicated that the Grade 10 Math ModelrnExams had moderate criterion related validity but suffered from weak content validity. The mainrnreason for this weakness is that the purpose of the exam was not clearly documented and hence,rnthis situation leads to unsystematic preparation of the exams which results in unintendedrnpractices in the education system. Therefore, the study pointed out some directions for possiblernsolutions and suggested for further research in the field.