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Missouri Car Seat Laws

Joanne Stene
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by Joanne Stene

In Missouri, children of all ages should use some device to keep them safe in a car. Whether that’s an infant seat for a baby or a seat belt for an older child, parents need to know the common Missouri car seat laws.

Here are the basics of car seat types and when Missouri law requires you to use them.

Driving in Missouri

Missouri Car Seat Laws

In Missouri, you can use a few types of car seats to secure your child. The best type of seat depends on the child’s age, weight, and height, so you may need to switch seats as they get older. However, Missouri car seat laws require parents to use different car seats as their child grows up.

Consider a few popular types of car seats and when to use them when driving in Missouri.

Rear-Facing Seats

Rear facing seat

Missouri House Bill 2199 proposes that children under two must be in a rear-facing car seat. Both the House and Senate have voted to pass the law, but no further action has been taken on it.

Once the law applies, parents will have to use a rear-facing car seat for their young children. State law already covers this to some degree because children under four years old must be in an appropriate child safety seat.

Children up to age 4 who weigh less than 40 pounds may ride in a rear-facing car seat as long as they are safe. Rear-facing seats should only be in the back seat of a car to avoid potentially harmful effects from the front airbags of a vehicle.

Missouri Infant Seat Laws

Infant seats are a type of rear-facing car seat, and they are generally for babies under 20 pounds. However, some new infant seats can support babies as they grow past 20 pounds. That can help parents keep the same car seat for longer.

An infant seat usually faces backward, and the baby sits slightly up rather than completely on their back. Parents can install an infant seat in their car’s back seat.

Even with small babies, it is essential for parents to use an infant seat. Holding a child in your lap is not recommended, and it can put your baby at risk during a crash. A proper infant seat will restrain your child and keep them safer than being in your lap.

Missouri Front-Facing Seat Laws

Forward facing

As children get a little older and bigger, they can move to sitting in a front-facing car seat. Many front-facing car seats can accommodate toddlers up to 40 pounds, which lines up with Missouri car seat laws.

These seats have children sit upright and face toward the front of the vehicle. Depending on the car seat, they may be able to support kids who weigh more than 40 pounds. As a child grows out of their infant seat, it’s important to consider when to move to a front-facing seat and then to a booster seat.

Missouri Convertible Seat Laws

Convertible car seat

A great option for parents is a convertible car seat. Missouri car seat laws don’t specify what type of car seat parents have to use, and a convertible model is more versatile than a rear-facing or front-facing seat.

You can first use them as a rear-facing seat for an infant. The seat can recline like a traditional infant seat, so you can make sure your baby is safe. As your child grows out of that, you can switch the car seat around so that your child faces forward.

Convertible seats have a higher back than booster seats, so they’re suitable for younger children. Some convertible seats also offer a booster seat configuration. Then, you can keep using the same seat as your child grows up even more.

Missouri Child Booster Seat Laws

Booster seat

When kids reach the ages of four to seven years old, they’re typically ready to sit in a booster seat. The Missouri booster seat law says that children who weigh less than 80 pounds and are less than 4’ 9 “ tall should use one.

A booster seat works with the traditional seat belt in a vehicle, so you don’t need much more to restrain your child. However, the booster can make the seat belt safer and more comfortable for your child until they’re big enough to no longer need it.

If a child reaches their eighth birthday but is still within the height and weight requirements, they should continue to use a booster seat. Once they are big enough, children can follow the Missouri seat belt law to stay safe in a car.

Missouri Seat Belt Law for Children

Once a child reaches 8 years old, weighs 80 pounds, and is 4’ 9” or taller, they can use the same restraints as adults. Missouri law does not require those children to keep using booster seats or car seats. However, children must wear a seat belt in most cases.

The main exceptions are if the child is in a school bus or another vehicle that can carry 10 or more people. Another exception is if a driver is transporting children within their immediate family and there are more children than seating areas. When that occurs, the children who aren’t in a seat should sit behind the front seat.

In all vehicles, children under age 13 are safest in the back seat. And unless those few exceptions apply, children ages 4 to 15 must wear a seat belt wherever they sit in a car. Children up to age 18 should wear a seat belt when riding in a truck, so that means they cannot ride in the bed of a truck.

If a child is using just a seat belt, it should be secure around the hips. The belt that goes over the shoulder should also be secure, and it shouldn’t cover the face or neck. If a child is big enough to not need a booster seat, but the seat belt is too high, a booster seat can still be appropriate.

Penalty for Law Violation

The penalty for violating Missouri car seat laws is $50, but you will also have to pay any court costs that come up. Drivers can also face a penalty if a child isn’t following the Missouri seat belt law. In that case, the cost is $10.

If you do violate Missouri booster seat law or car seat law, you can get your charges dismissed. You will need to go to your court date and provide proof that you have added the proper child safety restraint system based on your child’s age and size.

Can a Child Ride in the Front Seat?

While Missouri car seat laws don’t prohibit it, children should ride in the back seat for as long as possible. The back seat is safer, and it can protect smaller children better than the front seat. However, parents can allow their children to sit in the front seat once they’re big enough.

Allowing a child in the front seat is sometimes necessary if you are driving multiple children. You don’t have to worry about violating a Missouri seat belt law. But consider if you’re comfortable with your child sitting in the front seat of your car.


Missouri car seat laws are pretty straightforward. Parents must place their child in age-appropriate child safety seats until the child is 8 years old, weighs 80 pounds, and is at least 4’ 9” tall.

The Missouri booster seat law allows children slightly younger and smaller to use a booster seat with a seat belt. If you drive through Missouri with your children, make sure you use the right equipment to keep them safe and avoid any penalties.

About Joanne Stene
Joanne Stene
Joanne is a mother of 2 young girls and a technical writer with over 20 years of professional experience. She originally got interested in the topic of car seats as her two daughters were born and during the course of research into which seats to buy for her family. That interest has turned into a passion of sharing information on the Elite Car Seats website.
Joanne Stene
  1. This picture of the little girl in her car seat, rear facing with her tablet, needs her straps tightened. Probably should remove the shoulder pads as well. Besides trying to figure out if a child should be rear facing or forward, people also should know the safety about correctly buckling their child into the seat.

    1. Thank you for your insightful comments, Darvey. We use some stock images for our website when we don’t have our own photos to share. Typically, they’re pretty good and thoughtful, but you picked out some good themes here in that particular picture. In fact, I’m approving your comment here and will keep the image on the page as a learning example for future readers.

  2. So if my daughter is 8 almost 9 but doesn’t weigh 80 pounds and isn’t 4’9″ she has to be in a booster seat? Because she is only 59 pounds and maybe 4ft tall but I still have her in a booster seat she just doesn’t want to be in it

    1. Hello Jennifer, the law states that children 8 and over or weighing at least 80 pounds or at least 4’9” tall are required to be secured by a safety belt or buckled into an appropriate booster seat. Since your daughter doesn’t meet those thresholds, it appears that the booster seat is still appropriate.

  3. My child is about to 4 & weighs 47 pounds, Are they old enough for a booster seat or should we stick with the common carseat for a bit longer?

    1. Hi Hannah. The law states that children ages 4 through 7 who weigh at least 40 pounds must be in an appropriate child safety seat or booster seat unless they are 80 pounds or 4’9″ tall.

  4. My son is 6 years old 47 in tall and 49 lbs. Can he legally sit in the front seat on a booster seat?

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