To understand the genetic architecture and make inferences about transmissible resemblance of systolic and diastolic blood pressure (SBP and DBP) traits in relatives, the polygenic effect of individual alleles in terms of narrow heritability (h2) is usually assessed. The heritability estimates for BP traits are population specific parameters with a wide range in different studies (6-68%), and there is no comprehensive evidence comparing its source(s) of heterogeneity. To fill the gap, this systematic review and meta-analysis study was carried out. Using MeSH terms, 647 records were detected through searching, "Pubmed," "Ebsco," "Web of Science," and "Scopus" databases. From these, 24 relevant full-text articles with 47 comparisons for final quantitative meta-analysis were included in our review over the five continents. The additive genetic effects of both traits showed a widespread distribution (h2SBP: 17-52%, h2DBP:19-41%). Different categories of transmissible resemblance for BP traits were explained by ethnicity; higher heritability was estimated in Europeans and Mexican Americans, while lower heritability was seen in the Middle Eastern, Asians, Africans, Latinos, Hispanics, and American Indians. Low heterogeneity of polygenic effects was seen for both traits in subgroups of the Middle East, Asians, Africans, and Latinos, Hispanics, American Indians. However, there was a substantial heterogeneity of h2 within European and Mexican American studies. Neither pedigree type nor other covariates explained the variance of additive genetic effects of BP traits in different ethnicities.