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Best Trailer Hitch Lock Options of 2021: Keep Your Trailer Safe

Vehicle trailers can be used for a wide variety of things from recreation to heavy-duty work. Many people use them for their jobs, making them essential pieces of equipment used for everyday life. Some of the simplest trailers can be relatively inexpensive, but campers, trailers that tow cars, and others used for hauling can cost a pretty penny.

It is therefore important to do your best to protect your investment. The simplest way to do so is through the use of a trailer hitch lock. Trailers are very similar to wheels, in that they are some of the easiest automotive-related items to steal (learn more about wheel locks) since anybody with a trailer hitch could back up, hook up the receiver, and drive away. 

Protecting your property should always be a top priority, even if you do not live in a crime-ridden area. A trailer hitch lock is a very inexpensive way to protect a very expensive item, and most hitch locks are very easy to use. 

The Best Trailer Hitch Locks


1. AMPLock RV/Trailer Coupler Lock

AMPLock is a family-owned business that prioritizes safety and quality in all of its products. Their 2 5/16-inch coupler lock is specifically molded for a tight fit, eliminating the chances of prying. It also helps the cylinder lock to be almost entirely un-pickable. 

AMPLock’s patented two-lock system with an easy-to-use push-and-lock cylinder lock makes it easy to use for anybody. All of this ease of use does not come with compromise. The cylinder lock is designed to resist drilling, torch cutting, and even liquid nitrogen use. Additionally, it is designed to absorb shock and bend rather than break when under pressure.

Each customer receives a unique set of key and lock combinations to make sure that duplicates are avoided. But, if you need an additional key, or if your key is lost, more can be made to fit your specific lock.

2. Master Lock 377KA Trailer Hitch Lock

Master Lock has a long and well-respected history in the lock business, and for good reason. Their locks are widely known and used throughout the world. The 377KA Trailer Hitch Lock is a great product to protect against theft of vehicles, trailers, and RVs.

The 377KA fits a wide variety of trailer hitches, including 1 7/8-inch, 2-inch, and 2 5/16-inch sizes, making it quite versatile. Its three-step locking process makes locking your trailer simple and fast with an advanced locking mechanism that is built to resist picking.

Two keys are included in the purchase of each new lock. They are designed to be unique to your lock with no duplication. An added benefit of the 377KA is that it is constructed from zinc to rust and corrosion-resistant.

3. Trimax SXT5 Extended Receiver Lock

The Trimax SXT5 Extended receiver lock is a simple yet versatile lock designed to fit a wide variety of receivers. It is extendable to 3 ½-inches and has a diameter of 5/8-inch to fit all Class V receivers. It can also accommodate class III and IV receivers if necessary.

Its 100% stainless steel construction makes its design incredibly strong. It comes with a 5800-pound head pull strength, will not bend, and will not snap. The keyhole is sealed with a rubber cap that keeps out water, moisture, and other grime that could cause corrosion, and the locking mechanism contains an O-ring that performs the same task.

A type-A, high-security, seven-pin key that resists bending or breaking is included with the purchase of an SXT5 lock. And, the lock itself is pick-resistant and pry-resistant.

4. Tow Ready Gorilla Guard Coupler Lock

The Tow Ready Gorilla Guard coupler lock is a good, inexpensive way to keep your trailers from being stolen. This lock features a surround design that encloses the 2-inch coupler and locks it in place with a simple push of the lock. No tools are needed for locking safety or assembly.

Any lock comes with two keys and a unique key design to prevent copying and duplication as well as a 1-year limited warranty for additional peace of mind. The lock fits most 2-inch couplers, making it a universal fit and versatile lock for many different trailers.

Even though this lock is simple compared to others, its design shields the lock from picking and tampering. It is relatively inexpensive as well, retailing for much less than $50 in most locations.  

5. CURT 23079 Trailer Tongue Lock

The CURT 23079 Trailer Tongue Lock is similar to the Gorilla Guard in many ways, but it is more versatile, able to fit most 2-inch and many 1 7/8-inch couplers. It is a little pricier than the Gorilla Guard, even though the overall design is very similar.

Its coupler surround design prevents a trailer hitch from being attached, and it is locked from the front by one of the two included keys, rather than being locked from the bottom. As well as being made from aluminum, a snug overall fit prevents tampering and picking. 

The lock utilizes a grey powder-coated finish for its already robust resistance to weathering and corrosion. This also enhances its sleek and simple appearance. If this particular tongue lock is too small, CURT does offer the same design in larger dimensions.

Trailer Lock vs Hitch Lock vs Coupler Lock: The Differences Explained

best trailer hitch lock

Trailer locks, hitch locks, and coupler locks are differentiated by the purpose of the lock between the vehicle and the trailer. There are even more terms to designate a lock that is generally used as a theft deterrent for a trailer or a trailer hitch, but these are the most common terms.

Trailer locks and coupler locks are usually used interchangeably. They are locks that are fitted to an unattached trailer where a trailer ball would usually fit. This prevents someone from driving up, attaching to an unattached trailer, and driving off. 

Hitch locks can also be called receiver locks. Different types of receivers can be fitted to trailer hitches to accommodate different trailer coupler types. These receivers are usually just connected with a pin. Removing the pin is fairly straightforward, so a receiver lock is another important theft deterrent lock that usually is not mixed up with other types of trailer locking devices. 

Trailer Lock Designs Explained

The main types of anti-theft locks for trailers and hitches have been outlined above, but each type has distinctive designs for what each is made to accomplish.

Coupler/Tongue Locks

Coupler or trailer tongue locks are designed to surround and travel underneath the part of the trailer that connects to the ball. Of course, any piece of the lock that prevents the ball from attaching to the tongue is mainly there to prevent that from happening. The tongue surround design is mainly to prevent prying, shimmying, and tampering.

Many types of coupler locks come with a “dummy” ball that is inserted into the receiver that is held in place by the lock. Some more basic designs simply include an unattached ball and a metal bar that fits over the trailer coupler.

Hitch/Receiver Locks

 Hitch and receiver locks are designed like trailer pins, but with locks that can be secured in place. They are used in place of pins to ensure that the receiver or even an attached trailer cannot be removed.

Trailer Hitch Terminology

To better understand trailer locks and how they work, it is important to know some basic trailer and hitch terminology.


The most basic trailer term is a hitch. It is the part of the vehicle that serves as the connection point between the trailer and the vehicle doing the towing.


The coupler is the part of the trailer that hooks to the tow hitch receiver. It is hollowed out so that it fits over the trailer ball correctly. Once attached, it can be locked into place by tightening the latch on the trailer.


The tongue of the trailer is the part that extends out from the actual trailer and contains the coupler. Basically, it is everything that extends from the bed, housing, or RV part of any trailer.

Trailer Ball

The trailer ball is the rounded part of the hitch assembly that is connected to the tow vehicle that is meant to be mated to the trailer coupler.


Hitches and receivers are broken up into several categories that vary according to size and connector type. These categories are called hitch classes, and they are important to know when it comes to what kind of trailer you intend to pull. It is similar to knowing what type and size of tires your vehicle needs.

Final Thoughts

Trailer hitch locks are inexpensive and practical security devices that are widely accessible and simple to use for anyone who has a trailer. Trailers can be very difficult to track and return when stolen, and many people rely on them for their occupation or various recreational activities. 

Being so inexpensive and easy to use, it is difficult to justify not buying one. You do not have to live in a high-crime area for a trailer to be stolen from your property, seeing as how they can be quickly attached to any vehicle with an appropriate hitch.

Richard Reed
I've been a General Manager of a moving company and I've also been a Professional Mover for over 30 years. I've driven flat beds, reefers, dropdecks, moving vans, heavy machinery, etc. In my time as a Mover I've driven over 1,000,000 safe miles. My days of moving and driving truck are past me but The Vehicle Lab allows me to share the knowledge I've gained over the past 40 years.
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