Three-Year-Old Children: Physical and Mental Development

Three-year-old children experience great physical, cognitive, emotional, and social advances. Discover their main milestones.
Three-Year-Old Children: Physical and Mental Development

Last update: 26 March, 2022

Each stage of child development is important in its own way and contains very valuable milestones. However, three-years-old children are at an age of great advances. That’s because the cognitive and physical maturation that infants acquire at this time allows them to better explore their environment and hone their skills. If you have a three-year-old at home, here are the main milestones and advances you’ll observe in them.

It’s worth mentioning that three-year-old children are also in a transitional stage. Many children start daycare or pre-school at this age and their social world expands beyond their family. This allows them to receive richer and more varied stimulation, as well as to achieve greater independence and autonomy.

Physical development in three-year-old children

Although each child follows their own growth rate, in general, three-year-olds gain about 4.5 pounds and about 3 inches from their second birthday. In addition, the prominent, rounded abdomens of babies tend to flatten out, giving them a slimmer, sleeker appearance. Finally, most of them already have all of their baby teeth in their mouths.

Motor skills also make great strides at this age. In terms of gross motor skills, children can now run, climb, jump, and squat without support. Also, they’re able to alternate feet when going up and down stairs and can participate in play activities, such as pedaling a tricycle or kicking a ball.

Fine motor skills are also perfected, and at this time, infants can use cutlery, turn the pages of a book, or hold a pen correctly. In addition, thanks to their improved coordination, they’re able to perform two activities at the same time: For example, climbing the stairs while singing a song.

A three-yearh¡-old child pulling a toy truck down a dirt path.

Mental development in three-year-old children

On a psychological and emotional level, important events also take place that mark a before and after in their development. The following aspects are some of the most relevant.


Three-year-old children are in the middle of the famous tantrum stage. In reality, this is a developmental moment in which the child seeks to assert their identity as an individual and tends to oppose their parents in order to do so. When they don’t get their way, they may experience frustration that they don’t yet know how to handle, leading to a tantrum.

They’ll also demand greater independence: They’ll want to dress themselves, walk down the street without holding an adult’s hand, or pour their own milk into their breakfast cup. They’ll become increasingly autonomous and will need less and less help from their parents.

Sociability and emotional expression

At this age, children experience a wide range of emotions and often express affection spontaneously. Separation anxiety begins to decrease and they become progressively more comfortable in the presence of adults and unfamiliar children. Their social skills improve, especially with peers in nursery schools.

Thinking and reasoning

Your three-year-old already knows their name and age and identifies as a boy or a girl. They can also identify others in this respect.

They can memorize numbers in order and recite the letters of the alphabet, although this doesn0t always mean that they can recognize them individually or within words.

They’re also able to follow two- to three-step directions and instructions and to complete simple puzzles. They’ve achieved better attention management and can direct their attention voluntarily. In addition, their memory skills have increased and they’re able to recount past events and remember different concepts.

Their thinking isn’t yet logical and is conditioned by experience and what can be perceived through the senses. For your little three-year-old, it’s not yet possible to adopt or understand perspectives different from their own. However, they have a rich imagination that’s embodied mainly in symbolic play.

Toilet training

From the age of two, most children begin the process of toilet training. Therefore, at this time, it’s likely that your child shows interest in no longer using diapers and starting to use the toilet.

You should keep in mind that this is a gradual process, which begins with stool control during the night and then during the day. It then continues with daytime urine control and ends with nighttime urine retention.

Although 75-80% of children are ready to complete this process by age three, your child may need a little more time and that’s okay.

A toddler sitting on a potty.

Language and literacy

Language grows exponentially during this period. Your child begins to understand and use an increasingly large vocabulary, can form complete sentences with pronouns and plurals, and refines their pronunciation.

By the age of three, your child will probably be able to write their name (even if it’s irregular and disproportionate) and recognize it in writing. However, they still have a long way to go to master literacy, and this process shouldn’t be forced or accelerated.

Three-year-old children: A world of possibilities

In short, your three-year-old is in the process of opening up to the world: They’re exploring their horizons beyond the home and discovering new and wonderful personal skills. They love their budding independence, are fascinated by sounds and movement, and enjoy interacting with others.

Our recommendation is that you savor every second of this stage and treasure the precious memories you’ll have with your little one during this year of life.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Díaz, P., & Bonet, C. (2005). Las rabietas en la infancia: qué son y cómo aconsejar a los padres. Revista Pediatría de Atención Primaria, 7(25).
  • Sociedad de Pediatría de Asturias, Cantabria y Castilla y León. (2005). Control de esfínteres en los niños. SCCALP. Recuperado enero de 2022, de

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.