In adoption, it is common to consider the adopted child, the adoptive parents, and the birth mother as part of the adoption galaxy. Yet, birth fathers are often missing elements in adoption‐focused research. This article aims to comprehensively understand the current knowledge regarding birth fathers' experiences in adoption. Adapting the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses approach, this review identified 100 peer‐reviewed articles published from 2000 to 2022 on birth fathers in adoption. This article used a mixed‐methods approach to analyze the landscape of the current research. Quantitative analysis confirmed that birth fathers in adoption are under‐researched worldwide. In the qualitative analysis, the following themes emerged regarding birth fathers: a lack of openness, negative stereotypes, gatekeeping, and emotional impacts. The findings demonstrate the importance of considering the wishes and support needs of birth fathers when their child is being placed for adoption.