The purpose of this study is to find out the causes forrnstudents' deficiency in English with particular reference torng~ades 9-12 English curriculum and its implementation inrnschools at capitals of Ethiopian administrative regions.rnTo thi s effect}data on Grades 9-12 English curriculumrnobjectives and content have been secured ~,i th the hel p o frncurricular document analyses and unstructured interviews madernwi th members of the English Panel in the Institute forrnCurriculum Development and Research(ICDRJ .rnOn the other hand, info~mation on the curriculumrnimplementation is obtained through questionnaire andrninterviews conducted to grades 9-12 English teachers; classrnobservations; instructional media chec~~-lists; assessment ofrncourse and weekly lesson plans, examination and test papersrnin 10 senior secondary schools which have been selected withrnthe help o~ quota sampling techn ique.rnThe results o~ data analyses, interpretations andrndiscussions indicate that one of the causes for students'rndefi ciency in English is the design and implementation of therncurriculum, which in accordance to the findings of thisrnpaper, focus on:rnAmbiguity and insufficiency of therncurriculum objecti ves ; absence ofrncommunicative language; high dosage ofrngrammatical descriptions; irrelevance ofrnreading passages J vocabulary items andrne >! erci ses as cur-ricul urn contents andrntheir unsystematic selection andrngradation; shortage and or absence ofrnappropriate instructional facilities,rnplans, methods, techniques and evaluationrnstrategies for implementing it.rnIn synthesis , t hese findings reveal the pitfalls inrngrades 9-12 English curriculum and it s implementation whichrncaused students' deficiency in English; and hoped to servernpolicy m a~~ers , the ICDR and teachers as frame of referencesrnto change the curricul um and improve its instruction.