This study aims at constructing a vocational counseling program based on Gelatt model and measuring its effect on improving the level of vocational decision making among tenth grade students in The Sultanate of Oman. Sample of the study has been selected randomly from tenth grade students at the Public Schools during the first semester of the year 2006 2007.It consists of (132) students /males and females, tested by using two approaches: before and after applying the vocational program. measurement was done by using a questionnaire in order to measure the level of vocational decision making, which validity and reliability were checked. The sample of the study was divided randomly into two groups: experimental group consists of (67) student and control group consists of (65) student. The experimental group went through a guiding program in vocational decision making consists of (16) training session. Arithmetic mean and standard deviation as well as (2-way ANCOVA) were used to investigate the significance of differences between gender and group variables of the study sample. The results of analysis revealed that there is a statistical significance differences between the two groups in terms of the level of vocational decision making. According to experimental group, these differences refer to the guiding program. The results revealed an impact of the significant level (a ≤0.05) for the interaction between the group and the students gender in the comprehensive performance when taking the vocational decision. Where as, the improvement in the males performance when being explored to the guidance program, is different than the females to the same program and in favor of females. The results did not reveal any significant level (a ≤0.05) for the interaction between the program and the education level for father in the complete performance upon the vocational decision making measure. The results did not reveal any significant level (a≤0.05) for the interaction between the program and the education level for mother in the complete performance upon the vocational decision making measure.