Connection stiffness affects the behavior of wood structures. Methods to estimate nonrigid joint stiffnesses are essential for accurate structural analysis solutions. A theoretical model for predicting the rotational stiffness of nail joints was developed and experimentally verified. The complex joint action was decomposed into simple components and modeled with elastic springs representing the stiffness associated with nail-head embedment, shank withdrawal, and crushing at the interface between the main and side members. Test methods were developed for predicting these stiffnesses from the specific gravities of the joined members. The model was verified in the linear range by comparing experimental and predicted rotational stiffness for single and multiple-nail joints. Single-nail joints were constructed with nails oriented parallel and perpendicular to the main member grain. Excellent agreement was found between the predicted and experimental values. The advantage of the theoretical model is that a wide range of joint configurations with single and multiple nails can be rationally analyzed.