Background: Contraceptive use has increased markedly in the recent years in most developing countries, due to desire for smaller families; however, millions of women still want to delay or avoid pregnancy but are not using contraception to limit or to space their birth.Thus, the objective of this study is to assess unmet need for family planning among married women in Mekelle city, Tigray. Methods: Community based cross-sectional study was conducted among married reproductive age women. Data were collected from October, 15 up to Novmber, 15/ 2018. A total of 426 study participants were interviewed using a systematic random sampling technique. Structured and interviewer administered questionnaire was used to collect the data and were analyzed using SPSS version 22. Bivariate and multivariable logistic regression models were used to assess the predictors of the outcome variable. P-value of less than 0.05 was considered to test statistical significance. Results: The overall unmet need for modern contraception among the currently married women of reproductive age women was 19.7% (95% CI: 16.2%-23.7%) and of which 13.3% was unmet need for spacing and 6.4% was unmet need for limiting.Age of mother (25-34 years: AOR =2.79, 95%CI =1.03-7.60), occupational status of mother (AOR =2.72, 95%CI =1.72-4.02), number of living children (AOR =2.31 95%CI =1.09-4.84) and knowledge of mother about modern contraceptive methods (AOR =3.38, 95%CI=1.82-9.92) were independent predicators for unmet need for modern contraception. Conclusion: The prevalence of unmet need for contraception is low. Age of mother, occupational status of mother, number of children and knowledge of mother about modern contraceptive methods were the independent predicators for unmet need of modern contraception. Strong effort should be made by health care workers to reduce unmet need and policy makers should use different approaches to educate women about modern contraception and increase its utilization for spacing and limiting.