This is a list of law enforcement agencies in the Commonwealth of Massachusetts.
According to the US Bureau of Justice Statistics' 2018 Census of State and Local Law Enforcement Agencies (CSLLEA), the state had 374 law enforcement agencies employing 19,578 (sworn) personnel (27,489 personnel, total, including sworn and non-sworn positions), with an average of 284 sworn personnel per 100,000 residents (compared to the national average of 241 sworn personnel per 100,000 residents, with Massachusetts maintaining approximately 16% more sworn personnel per 100,000 residents than the national average).
Between the previous CSLLEA (in 2008) and the 2018 CSLLEA, Massachusetts saw an increase of 357 law enforcement agencies to 374 (an increase of 17 agencies or 4.6%). Sworn personnel would increase from 18,342 to 19,578 (an increase of 1,236 or 6.5%). Sworn personnel would increase from 280 per 100,000 state residents to 284 per 100,000 residents (an increase of 4 per 100,000 or 1.4%).
As of 2022, Massachusetts ranked 26th out of 50 in violent crime rates, ranked (45th out of 50) in homicide rates, and was the ranked second-lowest (48th out of 50) in property crime rates as of 2019.
Alcoholic Beverages Control Commission Enforcement Division special investigators, Massachusetts Department of Correction officers, Massachusetts Parole Board officers, Massachusetts Probation Service officers, and Massachusetts Trial Court Security Department officers are not subject to the MPOST-C's regulations nor certification process. This restricts their ability to act as law enforcement officers in all but very specific circumstances.
County sheriff's angencies are not automatically subject to the MPOST-C's regulations nor certification process. This restricts their ability to act as law enforcement officers in all but very specific circumstances. Sheriff's personnel that meet the MPOST-C standards and are certified, however, are considered "law enforcement officers" under Massachusetts law and are not subject to the same restrictions.
These are federal agencies that have common operations within the commonwealth.