IntroductionIn Ethiopia, undernutrition is the common public health concern, swaying the lives of lots of adolescent girls. Its sequelae are not only limited to them, but rather their upcoming offspring are vulnerable too. Even though some studies have been carried out in different parts of the country, the national pooled prevalence and determinants of undernutrition are not known. Therefore, this study is aimed at determining the pooled prevalence and determinants of undernutrition among adolescent girls in Ethiopia.MethodsPublished articles will be retrieved from databases such as Medline and PubMed. Electronic search engines such as Google Scholar and Google will be used. To identify eligible studies, the Joanna Briggs Institute quality appraisal checklists prepared for different study designs will be used. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist will be used to maintain the scientific robustness of the study. The presence of heterogeneity among studies will be examined by forest plot as well as I²heterogeneity test. Potential causes of heterogeneity will be explored by carrying out sensitivity and subgroup analyses. The DerSimonian and Laird random-effects model will be used provided that heterogeneity is observed. Publication bias will be examined by observing funnel plots, and objectively by Egger’s regression test. If the funnel plot is asymmetric and/or Egger’s test was found to be statistically significant (p<0.05), the trim and fill (Duval and Tweedie’s) analysis will be performed. The presence of a statistical association between independent and dependent variables will be declared if the p value is <0.05 with the 95% CI.Ethics and disseminationSince this is a systematic review and meta-analysis, ethical clearance will not be a concern. The results of the study will be published in a peer-reviewed reputable journal and presented at different scientific research conferences.Trial registration numberCRD42018106180.