When will my baby start to understand the word “no”?
This is a very common question among parents with babies around 6 – 18 months, who are just starting to be able to discover the world for the very first time. 

For these kiddos, everything is fun! Including the outlets, their sister’s “special toys,” the family pet, and anything else you don’t want them to touch! The earliest that children can understand the word “no” is around 9 months old. Even at this time, it takes a lot of reminding. For some children, it can be closer to 18 months before they truly understand what “no” means.

4 simple steps: connection, set expectation, teach, praise

These four steps can be a very effective and simple way to teach your child not only to understand the word “no,” but to also learn a new skill at the same time! When we say “no” to our child, it is important to show them what “yes” is at the same time. We want them to learn new appropriate things they can do when they are tempted to do the “no” behaviour. Here are some examples that tie this together:

Example: Your child is hitting your family cat.

Instead of:

“No hitting kitty”

“Stop hitting kitty!!”


Connection: “Looks like you are trying to play with kitty”

Set the Expectation: “No hitting kitty, it hurts her!”.

Teach them: “Yes, be soft to kitty” guiding their hand softly on the cat.

Praise: “Great job being soft to kitty!”

Example: Your child is yelling at you to get a snack.

Instead of:

“No whining!”

“Stop yelling at mommy!”


Connection: “It sounds like you are really hungry and you want a snack.”

Set Expectation: “I know you are really hungry, but I need you to ask me nicely for a snack… could you try that?”

Teach them: “Hey mommy, I’m hungry and need a snack – try saying it like that.”

Praise them: “I love how nicely you asked mommy! Here is your snack!”

Consistency is Key! In order to teach no, we need to be consistent with our “no’s.” Consistent loving boundaries keep kids safe and are a great way to love our little ones! Keeping your response to “no” behaviours consistent helps kids know what to expect, and will help them learn quickly.

Guard Your “No”: One research study revealed that many babies/toddlers here the word no up to 400 times a day! This research also suggests that the more a child hears the word “no” the more “no” loses its meaning. Try to use your “no” when you truly mean it and when you can follow through.

Give Yourself and Your Child Grace: It can be so frustrating when your newly walking baby is into everything. It can feel like they are intentionally trying to drive you nuts! The truth is, they are just learning and discovering the world for the first time. They are not intentionally trying to drive you crazy. They are trying to figure out what the boundaries are, what safety is, and what behaviour and activities are “yes’s” and “no’s”. In this season of life, give yourself and your child a lot of grace as you both figure out these boundaries! It can be a tough season, but soon they will understand “no” and “yes.”


Jess VanderWier

Registered Psychotherapist & Mom of 3

Learn More About Jess
  • Instagram
  • TikTok
  • Facebook