This study aims at developing and measuring the effectiveness of a collective counseling program in improving marital harmony among newly married female teachers in Al-Batinah South, Sultanate of Oman. The researcher developed a marital harmony scale and used that with (279) newly married female teachers. The sample of the study consists of (22) newly married female teachers who have achieved the lowest scores in the scale. The sample was distributed randomly into two groups: control group and experimental group; each group consists of (11) teachers. The experimental group received a collective counseling program that consisted of (16) counseling sessions which lasted for (7) weeks, two sessions a week. Each session took around (60-90) minutes. In order to test study hypothesis, the researcher used Mann-Whitney U Test. Results have shown that there are significant differences (a=0.05) between scores of control group and experimental group in both follow-up and post-evaluation. This indicates the effectiveness of the collective counseling program used in this study in improving marital harmony for newly married female teachers. Key words: marital harmony, counselling program.