Purpose: The current study examines bilingual children's development of Spanish and English morphosyntax structures over the period of 1 year. Identification of morphosyntax forms clustered by difficulty can elucidate their development and guide clinicians to select appropriate targets for intervention and monitoring. Specifically, we aim to evaluate how morphosyntax performance of bilingual children at the initial time point is related to their performance 1 year later and whether longitudinal development is different for children with developmental language disorder (DLD). Method: A total of 199 bilingual children (165 typically developing children and 34 children with DLD) between 7 and 10 years old completed a morphosyntax cloze task in both English and Spanish twice with 1 year apart. First, within-participant analysis of variance was used to identify morphosyntax clusters. We then used cross-lag analysis to study the relationship between morphosyntax clusters over time. Results: Morphosyntactic structures were clustered by difficulty in Spanish and English. There are three clusters of 1-3 morphosyntactic structures in Spanish and four clusters of 2-4 morphosyntactic structures in English. Cross-lag analysis demonstrated that for both languages, children's performance on simple items at Year 1 predicted performance on more difficult items 1 year later. Multigroup analysis indicated that most associations between morphosyntax clusters across time were not different for children with and without DLD. Conclusions: Findings on the difficulty levels of different morphosyntactic structures in Spanish--English bilingual children may provide implications for target selection when treating morphosyntax in this population. The study provides important insights into morphosyntactic change in bilingual school-age children in the United States, which are important to consider in bilingual language assessment and intervention.