The use of steel fiber reinforced concrete (SFRC) as a structural material has shown an ever-increasing growth. Steel fibers have a significant effect on the mechanical properties of reinforced concrete, especially on its tensile behavior. For SFRC modeling, it is necessary to determine the stress–strain equations. Due to the complexity of strain–strain tests and the lack of access to these results before modeling and design, determining these equations without testing is a modeling requirement. So far, limited studies have been conducted on estimating the SFRC tensile stress–strain equation based on other SFRC characteristics. In this study, the results of 41 experimental specimens collected from the literature are used to present an equation to estimate the SFRC tensile stress–strain diagrams using the genetic programming (GP) method. The proposed equation had acceptable accuracy compared to the experimental results and other equations presented in the literature.