Technical Abstract: Understanding and predicting crop phenology and canopy development is important for many reasons including improving the efficacy of management practices and accuracy of simulation models and decision support systems. This paper reports the status of a model for predicting crop phenology (Phenology MMS) that can be used independently to simulate crop development or incorporated into existing crop growth models. This new model is intended to synthesize and quantify the entire developmental sequence of the shoot apex of many crops, making this information readily available to users with limited knowledge of phenology or the crop being simulated. Developmental sequences for winter wheat and corn are presented as examples of model structure, use, and performance.