The Best Aftermarket Window Locks

Most windows come with standard locks, but if you have little ones at home, or if you want to beef up your security, a secondary window lock is a smart investment. We’ve done the research and compiled a list of the best window locks on the market to help you find the right ones for your home.

Compare the Best Window Locks

Best Adjustability

Best Portability

Best Childproofing

Product Image
Window Lock

Windobully Window Lock

Wedgit Twist Tight Security Bar

Ashtonbee Sliding Door Lock

Defender Security Sliding Window Lock

Maxdot Adjustable Sliding Window Lock

Andersen Double-Hung Window Opening Control Device

Canzak Window Restrictor Cable

Defender Security Double-Hung Wood Window Flip Lock

Best for...




Vinyl windows

Older windows

Wood frames


Wedge stop


Stop lock

Bar lock

Stop lock

Track lock

Track lock

Stop lock

Locking pin

Stamped steel


Top 3 Picks for the Best Window Locks

Windobully Window Lock

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. 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.

Pro Heading
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
Con Bullet Vulnerable to rust
Con Bullet Difficult to remove

Wedgit Twist Tight Security Bar

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. 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.

Pro Heading
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
Con Bullet No ventilation option
Con Bullet Grip strength required

Ashtonbee Sliding Door Lock

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.

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).

Pro Heading
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
Con Bullet Plastic construction
Con Bullet Potential to leave marks on glass
Con Bullet No installation instructions

Honorable Mentions

Defender Security Sliding Window Lock

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. 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.

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.

Canzak Window Restrictor Cable

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. 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.

Defender Security Double-Hung Wood Window Flip Lock

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. Like the Canzak, you’ll probably need to break out your power drill to install the Defender Flip Lock on your window.

Things to Consider

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.


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.

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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.