Verified Greenwich home security and alarm companies for alarm systems, cameras, smart locks, and monitoring - serving Old Greenwich, Riverside, Cos Cob, Byram, Glenville, Belle Haven and beyond.
A good security installer designs around your actual home, explains monitoring costs up front, and does not trap you in a punishing multi-year contract to get a fair price.
From backcountry estates to Old Greenwich colonials, Greenwich properties are managed like the portfolios of the people who own them. When you compare home security and alarm companies in Greenwich, ask every one of them the same three questions: are you licensed and insured for this exact work, who is actually showing up (your crew or a sub), and what does the warranty cover in writing.
Searching for home security and alarm companies near me in Greenwich? Everyone ranked below serves Greenwich and the surrounding neighborhoods, including Old Greenwich, Riverside, Cos Cob, Byram, Glenville, Belle Haven. Check the address and service area on a listing before you call, because the closest one is not always the one a search engine puts first.
Based on Google ratings and review volume as of September 2026, the top rated home security and alarm companies in Greenwich are Marshall Alarm Systems, Inc, Knight Security Systems, Advanced CCTV Alarm Systems. See the live ranked list, ratings, and contact details on this page.
Every company ranked on this page serves Greenwich and the surrounding area, including Old Greenwich, Riverside, Cos Cob, Byram, Glenville, Belle Haven. Open any listing for its address, phone number and service area, then call the two or three closest to you. Distance is worth checking yourself: the nearest home security company is not automatically the best one, so this page ranks on rating and review volume first and leaves proximity to you.
A good security installer designs around your actual home, explains monitoring costs up front, and does not trap you in a punishing multi-year contract to get a fair price.
Founding listings are free. We verify every business before it appears, so early businesses get the spotlight - your reviews, your services, and a direct line to customers searching in Greenwich right now.
Claim your free listingPrefer to talk? Call or text the Top Rated directory on (813) 454-0813. This is our number, not the number of any business listed here.