The abbreviation CMRR may refer to one of the following:
- Catskill Mountain Railroad — Operators of the former New York Central Catskill Mountain Branch from Kingston to Phoenicia (former Ulster and Delaware Railroad)
- Central Massachusetts Railroad — The former railroad forming part of the Boston and Maine Railroad system. For the current railroad, see Massachusetts Central Railroad.
- Common-mode rejection ratio — A measure of the capability of an instrument to reject a signal that is common to both input leads
- Chemistry and Metallurgy Research Replacement Facility - a nuclear facility at Los Alamos National Laboratory
- Committed Monthly Recurring Revenue — The value of the recurring portion of subscription revenue. A metric often used by SaaS (Software as a Service) companies, it excludes revenues that are not recurring even if such revenues are on a revenue recognition schedule.