The research aims to identify the effectiveness of a proposed program based on understanding learning in developing grammar teaching skills among fifth-grade science students. The researcher developed the educational program, which included the study tools represented by the proposed program and a test for grammar teaching skills. The researcher selected the Open Educational College, Balad branch in Salah al-Din province, for conducting the study. The second stage of the Department of Early Grades Teachers was chosen, and the research sample consisted of 60 students (both male and female). After preparing the program and its study tools, the researcher applied the program. The program’s topics were taught to the experimental group in 8 lectures per week to evaluate the achievement of the goals related to developing grammar teaching skills among the trainee teachers in the Open Educational College, second stage, in the Early Grades Teachers Department, for the subject of General Arabic. The post-test was conducted on both the experimental and control groups on Tuesday, December 6, 2019, and the final results were recorded. The research concluded the following results: There is a statistically significant difference at the level of (0.05) between the average scores of the experimental and control groups in the General Arabic subject in the post-test regarding the development of grammar teaching skills among students of the Open Educational College, in favor of the experimental group. The researcher recommended the use of modern programs in teaching General Arabic and other Arabic subjects