This book constitutes the refereed workshop proceedings of the 10th International Workshop on Structured Object-Oriented Formal Language and Method, SOFL+MSVL 2020, held in Singapore, in March 2021. The 13 revised full papers included in the volume were carefully reviewed and selected from 24 submissions. They are organized in the following topical sections: modeling and specification; model checking; specification and verification; and testing and formal verification. Due to the Corona pandemic this event was held virtually.