Best Security Companies in St. Louis (2026)

Updated November 2026 · By Kathleen Graves

Our verdict

Barcom Security is our top pick for security companies in St. Louis. It has served the greater St. Louis area for more than 50 years, covers homes and businesses alike — intrusion alarms, fire alarms, video surveillance, access control and intercoms — and backs it all with 24/7 TMA Five Diamond central-station monitoring, with a 5.0-star Google rating from 58 reviews (checked Nov 2026). The strongest alternative is PASS Fire and Security, in business since 1969, which pairs security systems with full fire protection and life safety under one roof.

Some St. Louis security firms install alarms, some watch over multi-location businesses remotely, and some put guards on site. Picking the wrong type is the most common mistake: a guard firm won’t wire your warehouse, and an alarm installer won’t staff your front gate. The companies below cover all three jobs, and every address, phone number, service and rating was checked against the business’s own website and its Google listing in November 2026. Ratings are reported as published and don’t decide the order. The order reflects editorial judgment about range of services, specialization, years in business and how clearly each firm publishes its details. No business paid for placement.

Best Security Companies in St. Louis at a Glance

1. Barcom Security

Google rating: 5.0 stars from 58 reviews (checked Nov 2026). 923 N Belt W, Swansea, IL 62226. Phone: (618) 800-2519. Website: barcomsecurity.com.

Best for: full-service residential and commercial security with Five Diamond monitoring.

Barcom is the broadest security firm on this list. It designs and installs intrusion alarms, fire alarm systems (including installation, inspection and monitoring), video surveillance, access control and intercoms for homes, businesses and enterprises, and monitors them around the clock from a TMA Five Diamond central station. The firm says it has served the greater St. Louis area, Central and Southern Illinois and Missouri for more than 50 years, and holds UL 2050 compliance and FM Approvals. Rather than naming brands, Barcom leads with its certifications — a sign of a firm that sells to customers who care about compliance as much as hardware.

2. Interface Systems

Google rating: no Google rating published (checked Nov 2026). 1844 Lackland Hill Pkwy, St. Louis, MO 63146 (headquarters). Phone: (800) 727-1668. Website: interfacesystems.com.

Best for: multi-location businesses that want video monitored remotely instead of guards on site.

Interface is the St. Louis-headquartered managed-security provider on this list, and it works differently from a local alarm installer: its interactive remote video monitoring centers act as virtual guards, verifying alarms by video before dispatching police, which cuts false alarms. It also manages intrusion and access control, fire alarm monitoring, video analytics, point-of-sale exception reporting and managed networks for restaurants, retailers and other multi-location enterprises. It does not sell to single homes. Third-party company profiles put its founding in 1995.

3. Tech Electronics

Google rating: 4.6 stars from 17 reviews (checked Nov 2026). 6437 Manchester Ave, St. Louis, MO 63139. Phone: (314) 645-6200. Website: techelectronics.com.

Best for: schools, hospitals and businesses that want security, fire and AV from one firm.

Tech Electronics has been in business since 1963 and is one of the few firms here that crosses from security into fire suppression, emergency and mass notification, visitor management, audio-visual and IT services. That breadth matters for its core customers — healthcare (including infant protection systems), education, government and commercial-industrial clients — where a single vendor for security, fire and communications simplifies compliance and service calls.

4. PASS Fire and Security

Google rating: no Google rating published (checked Nov 2026). 1938 Innerbelt Business Center Dr, St. Louis (Overland), MO 63114. Phone: (314) 241-0422. Website: passfireandsecurity.com.

Best for: bundling fire protection and security with one vendor.

Founded in 1969, PASS is the list’s life-safety specialist: access control and visitor management (including weapon detection), fire alarms, fire suppression, intrusion detection, video security and data storage, all monitored from a 24/7 UL-listed 5-Diamond central station. Its staff includes NICET Level I–IV technicians, and it handles inspections and compliance work such as emergency responder communication enhancement system (ERCES) testing. Named brands on its site include Software House, Avigilon, AMAG, March Networks, RS2 and Potter. It serves the greater St. Louis metro plus Central and Southern Illinois.

5. Philibert Security Systems

Google rating: no Google rating published (checked Nov 2026). 735 Marshall Ave, St. Louis, MO 63119. Phone: (314) 962-2000. Website: philibertsecurity.com.

Best for: homes and small businesses that want a local installer with home automation.

Established in 1971, Philibert is a St. Louis local covering commercial and residential security, commercial and residential fire detection, card access and CCTV, home automation, low-voltage wiring and 24/7 UL-listed central monitoring. Its site names its equipment lines — DSC, Bosch, Honeywell, Napco, Pelco, Silent Knight, System Sensor, Altronix and Telguard — which makes it easy to compare against what you already own. It serves the St. Louis metro on both sides of the river.

6. Midwest Alarms Plus

Google rating: no Google rating published (checked Nov 2026). 2801 Meramec St, St. Louis, MO 63118. Phone: (314) 481-5518. Website: midwestalarmsplusincstlmo.com.

Best for: a custom-designed system from a South St. Louis family firm.

Midwest Alarms Plus is a family-owned firm in business since 1982, per directories, that custom-designs, installs and services security systems, surveillance cameras, intercoms, fire alarm systems and card access for residential, commercial and industrial customers across the greater St. Louis area. It is the neighborhood-scale pick on this list: no national call center, and a shop that designs around your building rather than selling a fixed package.

7. Gateway Alarm, Inc.

Google rating: no Google rating published (checked Nov 2026). 5923 Weber Rd, St. Louis, MO 63123. Phone: (314) 487-2224. Website: gatewayalarm.com.

Best for: commercial clients that want alarms, cameras and building automation in one app.

Gateway Alarm has served the St. Louis area since 1979, per directories, with commercial and residential alarm systems, analog and network cameras, intercom and telephone entry systems, access control, intrusion alarms and building automation controlled from a smartphone app, built on the Alarm.com platform. Its work leans commercial.

8. American Digital Security (ADS)

Google rating: no Google rating published (checked Nov 2026). 859 Horan Dr, Fenton, MO 63026 (St. Louis office). Phone: (636) 305-1010. Website: americandigitalsecurity.com.

Best for: multi-site commercial and education facilities that need design, install and ongoing service.

ADS is a Missouri-based integrator with offices in Fenton (St. Louis), Liberty/Kansas City, Wichita and Junction City, Kansas. It designs, installs, services and maintains integrated video surveillance, access control, alarms and monitoring for education, commercial and specialty facilities, with support for multi-location customers. The firm does not publish a founding year on its site, and its brands are not named there.

9. Allied Universal Security Services

Google rating: no Google rating published (checked Nov 2026). 2258 Schuetz Rd, St. Louis, MO 63146. Phone: (314) 241-4220. Website: aus.com.

Best for: guard staffing, patrols and transit-site coverage.

Allied Universal is the guard-services pick: armed and unarmed security officers, patrols and risk consulting across the greater St. Louis area, including MetroLink transit platform security, plus a second Metro East office in Belleville, IL. If your need is people on site rather than equipment on the wall, this is the category to shop — and Allied is the largest provider of it locally. Branch years in business are not published.

10. Securitas Security Services USA

Google rating: 2.0 stars from 2 reviews (checked Nov 2026) — a thin base, read with caution. 55 W Port Plaza Dr #750, Maryland Heights, MO 63146. Phone: (314) 231-2122. Website: securitasinc.com.

Best for: large-site guarding with national backing.

Securitas provides on-site guarding, mobile patrols, remote guarding, electronic security, fire and safety services and corporate risk management in the St. Louis area. The parent company dates to 1934, though branch years are not published. Its Google rating rests on just two reviews, so it should not be read as a verdict on the branch — it is included for its scale and range of guarding services, not its rating.

How We Ranked These

We started with the St. Louis-area businesses that actually provide security: alarm installers, commercial integrators and guard firms. We checked each one’s address, phone, services, brands and years on its own website in November 2026, and each Google rating on its Google listing. Then we ranked them on these criteria:

• Services offered: whether the firm installs alarms, fire systems, video and access control, monitors them, staffs guards, or does several of these. Firms covering more of the job ranked higher.
• Specialization: residential, commercial, multi-location enterprise, or guard services — matched to the buyer each firm actually serves, rather than comparing a guard firm against an installer on the same yardstick.
• Google rating and review count: as published on each Google listing in November 2026. We read them together, since a 5.0 from 58 reviews and a 2.0 from 2 reviews aren’t directly comparable — and seven firms on this list have no Google rating published at all, which we say plainly rather than filling in a third-party score. Ratings informed the order but didn’t set it.
• Years in business: how long each firm says it has served the area, from Barcom (50+ years) and Tech Electronics (since 1963) to PASS (since 1969) and Philibert (since 1971).
• St. Louis service area: where offices sit and where technicians and guards will go, including St. Louis County, St. Charles County and the Metro East.
• Published details: how clearly a firm states its services, brands, monitoring credentials and policies.

No business paid for placement. Barcom ranks #1 because it combines the broadest offering — residential and commercial alarms, fire, video, access and intercoms — with the longest track record and the highest verified Google rating, backed by TMA Five Diamond monitoring. The mix of installers and guard firms is on purpose: if you need people on site, an alarm panel won’t help, and vice versa.

Tips for Choosing a Security Company in St. Louis

Decide first: equipment or people. Alarm installers and integrators (Barcom, Tech Electronics, PASS, Philibert, Midwest Alarms Plus, Gateway, ADS, Interface) sell and monitor systems. Guard firms (Allied Universal, Securitas) staff sites. Some jobs need both.

Ask who watches the alarm. A UL-listed or TMA Five Diamond central station (Barcom, PASS) means trained operators verify signals around the clock; a self-monitored app leaves response to you.

Bundle fire with security when you can. Barcom, PASS, Tech Electronics and Philibert all handle fire detection or suppression alongside security, which means one vendor, one monitoring bill and one service call.

Local installer vs. national call center. A St. Louis shop (Philibert, Midwest Alarms Plus, Gateway) services what it installs; a national provider may subcontract. Ask who actually shows up for a repair.

Get the monitoring terms in writing. None of the firms on this list publish prices, so ask about contract length, monthly monitoring cost, who owns the equipment and what happens if you cancel — before the install, not after.

Match the firm to your building. Multi-location businesses should talk to Interface or ADS; schools and hospitals to Tech Electronics; a single home or shop to Barcom, Philibert or Midwest Alarms Plus.

Frequently Asked Questions

How much does a security system cost in St. Louis?

None of the firms on this list publish prices. Cost depends on the size of the property, the number of cameras, sensors and access points, and whether you add 24/7 monitoring — so every firm here quotes after a site survey. Ask for the equipment cost, the monthly monitoring fee and the contract length in writing before you sign.

How do I choose between an alarm company and a guard service?

Choose an alarm or integrator firm (Barcom, Tech Electronics, PASS, Interface, ADS) when you need detection, cameras, access control or monitoring of a property. Choose a guard firm (Allied Universal, Securitas) when you need people on site — a staffed entrance, patrols, or coverage of a large or high-traffic site such as a transit platform. Some sites need both, and several firms on this list pair electronic security with guarding options.

Which security company on this list is highest-rated on Google?

Barcom Security, at 5.0 stars from 58 Google reviews (checked Nov 2026). Tech Electronics is next among rated firms at 4.6 stars from 17 reviews. Seven firms on this list have no Google rating published — that means no rating on their Google listing, not a bad rating — and Securitas’s 2.0 stars rest on just two reviews, so it should be read with caution.

Should I bundle fire alarms with my security system?

If your building needs both, yes — one vendor means one monitoring contract and one service call. Barcom, PASS Fire and Security, Tech Electronics and Philibert all handle fire detection or suppression alongside security systems. PASS is the most fire-focused of the four, with NICET-certified staff and inspection and compliance work.

Do these companies serve homes, businesses, or both?

Both, depending on the firm. Barcom, Philibert, Midwest Alarms Plus and Gateway Alarm serve homes and businesses. Interface Systems and American Digital Security are commercial and multi-location only. Allied Universal and Securitas provide guard services rather than home alarms.

What should I ask before signing a monitoring contract?

Ask how long the contract runs, what the monthly monitoring fee covers, who responds when an alarm triggers and how fast, whether a UL-listed or Five Diamond central station monitors your system, who owns the equipment if you cancel, and who performs repairs. Barcom and PASS both publish Five Diamond or UL-listed monitoring credentials; for other firms, ask directly.

Updated November 2026 by Kathleen Graves.