This study aimed at identifying the types of questions that are posed or asked by the students of the 100 grade basic education in the science subject, as per Harlen's classification, and its relation with their learning and gender. The study sample consisted of 112 students, of whom (49) are males and (63) are females, who were selected from two schools in the Directorate General for Education in the Governorate of Muscat for the academic year 2012-2013. For answering the study questions, the researcher has used three instruments: teaching situations test, which are consisted of four different educational situations requiring the students to pose from 5 to 6 questions for each in any interrogative pattern they view adequate. The second instrument was observation tool which was used to record the questions that had been posed by students during science lesson. The third instrument was focus groups which was used to provide the researcher some explanations for the study results. Validity of the first two instruments has been proven when exposed to five specialized expertise in science education. The validity of focus group questions was done by the researcher supervisors. The reliability of analysts has been confirmed through computation of (Holsty's) reliability coefficient, which scored (0.85) by three analysts for a sample of questions posed over teaching situations. Moreover, reliability of the observation sheet also been confirmed by using the coefficient of agreement between observers, this coefficient scored (0.85) which is deemed an indicator valid for the study objectives. The study results indicated that the questions posed about facts scored the highest percentage among the categories of posed questions according to Harlen's classification; that's (80.54%) for the teaching situations test, and (81.71%) for the classroom observation, while philosophical questions scored the lowest percentage (1.13%) for teaching situations test according to Harlen's classification; and haven't been posed during the teaching process. The results also showed existence of differences of statistical signification between types of students' questions depending on the level of learning variables and gender. According to these results, the study recommended that more attention shall be given to all kinds of students' questions including philosophical questions, and that those questions shall be used as an effective strategy in teaching sciences. In addition, it recommended that students shall be trained and encouraged to pose questions and formulate the same in a correct and scientific style especially the investigable questions for male students. Moreover, it recommended that further studies shall be conducted on the subject of students' questions.