This paper presents two concurrency control protocols for real-time object-oriented systems. One of the protocols is designed for single-node systems and the other is for distributed systems. Both protocols combine the features of semantic concurrency control for added concurrency, with priority ceiling techniques for deadlock prevention and bounded priority inversion. A version of this paper appeared in the International Journal of Computer Systems Science and Engineering - Special Issue on Object-Oriented Real-Time Distributed Systems, v. 14. no.4.