The purpose of this study is to classify and to analize the instructional objectives in teacher's guides of high school earth science course. The Romey's definition of instructional objectives was based for classification. The results of the study show that approximately 77 percent of total action verbs appeared in all teacher's guides are classified as level NO and level O. The dominant usage of such non-inquiring words may prevent the students from doing investigative activities. The level NO verbs reveals the vagueness of instructional objectives of the guide books themselves. Also, the frequent appearance of level O verbs mean that the books emphasize students recall behavior more than experimental, observational, interpretative and synthetic behaviors. Meanwhile, even the words requiring investigative activities are also mostly classified as low levels and fail to lead the students to grasp major concepts or to show original thoughts. The repeat usage of some particular words in stating instructional objectives, which is prevailing tendency of most book, exposes the monotony in instructional functions of those teacher's guides.