AbstractDespite extensive investigations of bond stress versus slip modeling for RC structures, most existing bond stress–slip models are incomplete, discontinuous, and insufficiently accurate. These problems can cause nonconvergence and other difficulties in computational simulations of concrete structures that use bond-slip models. Through systematical analyses of an existing database of bond-slip behavior and data regressions, this work develops a unified bond stress–slip model that overcomes these difficulties and is suitable for numerical simulations. The model is given by a single and mathematically continuous equation that does not distinguish between plain and confined concrete or splitting and pullout failure because such judgments are arrived at automatically by evaluating the model parameters. Furthermore, the model outperforms the existing models in the precision of its predictions.