The Best Aftermarket Window Locks

We researched window locks and scoured user reviews to find the best construction, installation ease, and low price points.
Best for adjustibility
Best for portability
Budget pick
Best for crank windows
Best for renters
Defender Security Sliding Window Lock
Defender Security Sliding Window Lock
  • Icon Pros  Light
    Adhesive- and tool-free installation
  • Icon Pros  Light
    Sliding windows

Most windows come with standard locks, but if you need to baby-proof your home or beef up your security, a secondary window lock is a smart investment. We’ve compiled a list of the best window locks on the market to help you find the right ones for your home—starting with our favorite overall pick, the Windobully Window Lock.

Compare the best window locks

Product
Price
Style
Learn more
Read review

Best for adjustability

Windobully Window Lock

Windobully Window Lock

Stop lock

Best for portability

Window security bar

Wedgit Twist Tight Security Bar

Bar lock

Budget pick
Defender Security Double-Hung Wood Window Flip Lock

Defender Security Double-Hung Wood Window Flip Lock

Stamped steel

Best for crank windows
Canzak Window Restrictor Cable

Canzak Window Restrictor Cable

Locking pin

Best for renters
Defender Security Sliding Window Lock

Defender Security Sliding Window Lock

Track lock

Best for childproofing

Sliding door and window lock

Ashtonbee Sliding Door Lock

Stop lock

*Amazon.com price as of 8/30/2021 at 8:00 a.m. (MT). Read full disclaimer.

Best window lock reviews

1. Windobully Window Lock: Best for portability

Best for adjustability

*Amazon.com price as of 8/30/2021 at 8:00 a.m. (MT). Read full disclaimer.

The Windobully lock earned the top spot on our list because it’s easy to install and it’s adjustable. To install it, you just peel and stick a 5.5″ stainless steel strip vertically to the glass on the top sash of your window, then insert the adjustable plastic catch into the strip.

Pro Heading
Pros
Pro Bullet Easy installation
Pro Bullet Adjustable opening widths
Pro Bullet Removable pieces
Pro Bullet 300 lb. resistance
Pro Bullet Mounted holder for catch piece
Con Heading
Cons
Con Bullet Vulnerable to rust
Con Bullet Difficult to remove

You can slide the catch down to adjust the window opening. And the teeth inside the metal strip keep it from sliding back up—and keep your window from going up when it hits the catch. If you want to have your window fully open, just squeeze the sides of the catch to detach it from the metal strip.

We like that the Windobully lets you decide how wide you want your window to open every time you use it. But make sure it’s in the right spot before you mount it, because it’s difficult to remove once it’s stuck in place. We also found that the metal strip is susceptible to rusting from window condensation.

2. Wedgit Twist Tight Security Bar: Best for portability

Best for portability

*Amazon.com price as of 8/30/2021 at 8:00 a.m. (MT). Read full disclaimer.

The Wedgit Twist Tight Security Bar works a lot like a door security bar that jams under a door knob. The Wedgit is made of high-impact polymer, and you can adjust its length using its locking pin and twisting tension feature.

Pro Heading
Pros
Pro Bullet Portable design
Pro Bullet 15″–25″ adjustable length
Pro Bullet 450 lb. resistance
Pro Bullet Excellent customer service
Pro Bullet Versatile design for windows and doors
Con Heading
Cons
Con Bullet No ventilation option
Con Bullet Grip strength required

The bar also attaches to the inside of your window frame with a peel-and-stick hinge, so you can easily pivot it out of the way into a horizontal position (or vertical for horizontal sash windows) when you want to open the window completely.

The design of the Wedgit doesn’t allow for a ventilation option for double-hung vertical sash windows, but we like that you can use it for narrow patio doors if you need some added security. You’ll need some grip strength to twist the bar enough to release tension and move it out of the way, so it’s great for keeping young children safe.

3. Defender Security Double-Hung Wood Window Flip Lock: Budget pick

*Amazon.com price as of 8/30/2021 at 8:00 a.m. (MT). Read full disclaimer.

If you’ve ever tried to overpower a doorstop, you probably know that a wedge puts up a strong defense against direct force. The Defender Flip Lock’s simple wedge design gives you tough security that you can lock and unlock with ease.

It’s only two inches long, so it’s very discreet, but its stamped steel construction isn’t easily overpowered. You’ll probably need to break out your power drill to install the Defender Flip Lock on your window.

Pro Heading
Pros
Pro Bullet Brass finish
Pro Bullet Swings out of the way
Con Heading
Cons
Con Bullet For wood windows only

4. Canzak Window Restrictor Cable: Best for crank windows

Best for crank windows

*Amazon.com price as of 8/30/2021 at 8:00 a.m. (MT). Read full disclaimer.

The most versatile lock on our list is the Canzak Window Restrictor Cable. You can use it to secure any opening in your home—even crank windows. Its design is similar to chain locks on apartment doors: you attach one side to the moving part of the window, and the other to the frame. When the cable is attached, the window can only be opened as far as the steel cable will stretch. 

Pro Heading
Pros
Pro Bullet Works on any kind of window
Pro Bullet Key required
Con Heading
Cons
Con Bullet Tools required for installation
Con Bullet Doesn't lock windows completely shut

You can’t use it to keep your windows locked shut unless you maximize the distance between the two attachment points (which might make it hard to lock and unlock,) so we recommend using it alongside a standard window lock. You’ll need a key to unlock and detach the cable, and you’ll need some skills with a screwdriver to complete this installation.

5. Defender Security Sliding Window Lock: Best for renters

*Amazon.com price as of 8/30/2021 at 8:00 a.m. (MT). Read full disclaimer.

The Defender Security track lock attaches to your window track using a two-step process. First, you’ll turn the handle to pinch the lock onto the track, then you’ll turn the lever over to secure it even tighter, like a clamp.

Pro Heading
Pros
Pro Bullet Hardware-free installation
Pro Bullet Diecast construction
Pro Bullet Move to any position
Con Heading
Cons
Con Bullet May come loose over time
Con Bullet Installation requires a strong hand
Con Bullet Not very childproof

This fastening method helps you get maximum friction between the lock and the track so that the window won’t budge, even with applied force. It’s easy to remove—just flip the lever—but that means it might not be the best choice if you have curious little ones.

We like that this lock doesn’t leave unsightly marks on your windows and that you can move it to any position along the window track. Its sturdy diecast construction is another feature that sets it apart from similar window locks. But we’ve found that it may weaken if you frequently lock and unlock it to adjust its position.

6. Ashtonbee Sliding Door Lock: Best for childproofing

Best for childproofing

*Amazon.com price as of 8/30/2021 at 8:00 a.m. (MT). Read full disclaimer.

Despite the name, the Ashtonbee Sliding Door Lock is also a great kid-proof window lock. Its design is easy for parents to operate, but tough for kids to crack. It’s made of plastic, so it’s not ideal for deterring burglars, but it’s simple to install and doesn’t require keys or muscle to open.

Pro Heading
Pros
Pro Bullet Childproof design
Pro Bullet BPA-free plastic
Pro Bullet Keyless operation
Pro Bullet Peel-and-stick installation
Pro Bullet One piece
Con Heading
Cons
Con Bullet Plastic construction
Con Bullet Potential to leave marks on glass
Con Bullet No installation instructions

To operate the Ashtonbee, you flip out a latch and lock it in place. The latch acts as a barrier, preventing the window from opening. To open the window fully, just release the lock, and the latch slides back down so it’s flush against the rest of the device (and won’t block the window from sliding open).

More window locks we considered

Maxdot Adjustable Sliding Window Lock

The Maxdot Adjustable Sliding Window Lock is another track lock device, but it secures to the track using a key. This makes it safer for homes with small kids, as long as you keep the keys out of reach. The key is designed like an Allen wrench, so you can turn it more for a tighter fit, and the bright yellow plastic key handle makes it easy to find, even in a junk drawer.

The Maxdot’s design makes it ideal for older, thicker framed windows, but it might leave a mark when it’s tightened. Like the Defender Sliding Window Lock, you can easily adjust the placement of your Maxdot on the window track to allow the window to be opened wider or be fully locked shut.

Andersen Double-Hung Window Opening Control Device

We like the unique design of the Andersen lock, because you can open your window without having to remove the lock, and it locks itself in place again automatically when you shut the window. This is one of the few locks on our list that requires screws, but it also meets the ASTM requirements for Window Fall Prevention Devices with Emergency Escape and (Egress) Release Mechanisms.

It’s made of metal and designed to work only for windows with wood frames. You can’t make any adjustments to the locking height once you’ve installed it, but you could install a second device to a different height to allow for a ventilation setting.

Things to consider before buying window locks

Different styles of windows open and close differently, so the style of lock you’ll need depends on the type of windows you have. Here are the four main types of moveable windows, along with the types of window locks that work best for them.

1. Single- or double-hung sash

A sash window has one or two sashes that can slide up and down on tracks in a frame. Stop locks, bar locks, track locks, locking pins, and wedge stops all work for single-hung or double-hung windows.

2. Casement

A casement window is hinged on the side and opens outward with a turn crank. Locking pins are the best types of locks for casement windows.

3. Awning

An awning window opens outward with a hinge at the top of the window. Locking pins work well for awning windows.

4. Slider

Slider windows have one or two sashes that slide sideways on a track. Stop locks, bar locks, track locks, locking pins, and wedge stops are all suitable sliding window locks.

Final word

The Windobully Window Lock ticks a lot of boxes:

  • Excellent adjustability
  • Isn't easy for kids to remove
  • Good for renters (take care not to peel paint)

It's our overall best choice for all sliding windows. 

FAQs

Both single-hung and double-hung windows have two sashes, but in a double-hung window, both sashes can move up and down. In a single-hung window only one window sash moves, while the other remains stationary.

Because there are so few situations where you might need to remotely lock or unlock a window, smart lock technology is currently limited to doors. But many security systems integrate smart window sensors.

Locks on window screens are kind of like locks on journals—they might make you feel better, but anyone with determination can simply cut right through the flimsy material they’re attached to. And when it comes to keeping kids safe, you should never rely on a screen to keep a child from falling out of a window. Screens are for keeping bugs out, not for keeping children in.

If you want to maintain air flow but prevent anyone from going in or out of your home through an open window, install a window sash lock that allows for ventilation. Mount it so that the window sash doesn’t open any wider than four inches.

No matter what type of lock you get, it will work best if the mounting site is clean and dry. Use the opportunity to clean up your windows in preparation for the lock—screen, sill, and tracks included.

How we reviewed window locks

We evaluated several types of window locks (such as track locks, wedge locks, and bar locks) to find those with the best construction, easiest installation, and affordable price tags. We also read user reviews to determine how the products perform in the real world. 

Learn more about our methodology.

Related articles on SafeWise

Disclaimers

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply to the purchase of this product. Safewise.com utilizes paid Amazon links.

Certain content that appears on this site comes from Amazon. This content is provided “as is” and is subject to change or removal at any time.

Kasey Tross
Written by
Kasey Tross
Kasey is a trained Community Emergency Response Team (CERT) member and a freelance writer with expertise in emergency preparedness and security. As the mother of four kids, including two teens, Kasey knows the safety concerns parents face as they raise tech-savvy kids in a connected world, and she loves to research the latest security options for her own family and for SafeWise readers.

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  • Karen Quish

    Do any of these window locks comply with the new building code laws and child safety for windows?

    • Katie McEntire

      Thanks for the great question, Karen! All of these products are removable (by an adult), so if you’re concerned about using one in a space that you rent, they should all be within compliance. Of course, building codes vary from place to place, so it’s best to look up the laws in your area.