Objectives: The purpose of this study was to evaluate the mediating effect of family strength on the relationship between self management and quality of life for pregnant woman with gestational diabetes mellitus. Methods: A convenience sample of 120 pregnant woman with gestational diabetes melli- tus was recruited. SPSS PROCESS Macro Model 4 was applied to confirm the mediation effect, and boot strapping using a 95% confidence interval was performed to detetmine the statistical significance of the indirect effect. Results: Family strength had a mediating effect in the relationship between self management and quality of life among pregnant woman with gestational diabetes mellitus. Conclusions: Based on the findings of this study, family strength should be considered when developing a program self management to improve the quality of life for pregnant woman with gestational diabe- tes mellitus.