15-Year-Old Child Development Milestones

Your child’s growth and development at age 15

The years between 15 and 18 can be instrumental in helping your teen mature and gain the skills she needs to become a responsible adult.

There's a good chance, however, that your 15-year-old will think she's ready to take on the world now. And she may insist she already knows everything. That know-it-all attitude with a hint of rebellion can be par for the course for 15-year-olds. 

Understanding your teen’s development can be instrumental to successful parenting during mid-adolescence.

15 year old child development milestones
Illustration by Emily Roberts, Verywell

Physical Development

Most girls have reached their full height by age 15. Many of them are insecure about their appearance, especially their weight. Nearly half of all high school girls diet to lose weight.

Fifteen-year-old boys may continue growing for another year or two. Usually, around this age, their voices become deeper and they may begin to grow facial hair. They gain muscle rapidly at this age.

Key Milestones

  • Boys' voices grow deeper
  • Boys begin to grow facial hair
  • Girls have reached their full height

Parenting Tip

Familiarize yourself with the signs and symptoms of eating disorders and other mental health problems. If you suspect your child has an eating disorder, body image issues, or mental illness, seek professional help.

Emotional Development

At the age of 15, teens start to think about what it would be like to live out on their own. While some teens may be imagining college, others may be thinking about getting their own apartment.

Your 15-year-old may become stressed about grades, relationships, and other teenage issues. And she may be very concerned with her appearance.

Most teens begin to engage in less conflict with their parents around age 15. They show more independence from their parents while also showing a greater respect for the rules when privileges are contingent on their behavior.

Many 15-year-olds are dealing with a fair amount of stress. Some of them may struggle academically while others are dealing with romantic issues and perhaps even their first sexual experiences.

Key Milestones

  • Go through less conflict with parents
  • Show increased independence from parents
  • Exhibit greater emotional regulation skills

Parenting Tip

Make your teen's privileges contingent on his ability to be responsible. Tell him he can earn freedom by showing you that he's able to handle more independence.

Social Development

Friends are very important to 15-year-olds. And it’s important to know who your teen is spending time with because they often experiment with different personas and activities based on what their peers are doing.

By age 15, many teens have a strong interest in romantic relationships. While some relationships may mostly evolve over social media or text message, others will want to spend a great deal of time with their romantic interest.

Most 15-year-olds are aware of their sexuality and show a budding interest in sexual activity.

Don’t be alarmed if your teen wants to spend a lot of time in his room by himself. Unless you see warning signs of mental health problems, an increased desire for privacy can be normal.

Key Milestones

  • Have an interest in romantic relationships
  • Have a deeper capacity for caring and developing more intimate relationships
  • May struggle with peer pressure

Parenting Tips

At this age, most teens still struggle a bit with maintaining healthy relationships, with peers and in their budding romantic interests. Make sure your teen is hanging out with healthy people and establish clear dating rules.

Cognitive Development

It’s normal for teens to be rather argumentative at this stage. No matter what you say, your teen may want to debate the opposite point of view. That’s your teen’s way of asserting his independence and showing off the fact that he can see viewpoints from another angle.

Many teens begin thinking more about their future during this time. They’re usually able to start identifying potential career aspirations or college plans.

Most 15-year-olds are able to give reasons for their own choices, including what was right or wrong.

Speech & Language

Some teens at this age can talk to their friends all evening, despite seeing them all day at school. Yet when asked about their day by their parents, they may have very little to say.

Most 15-year-olds often prefer to communicate via text message and social media. They may find blogging or writing to be a helpful way to express themselves.

Reading and social experiences play a big role in a teen’s language and vocabulary development.

Most 15-year-olds can communicate in an adult-like fashion and are able to hold appropriate conversations. They tell more involved stories and are able to use more sophisticated communication skills.


Most 15-year-olds have specific interests or hobbies that they enjoy. Whether they like video games, sports, music, or movies, they can identify activities that bring them pleasure.

While some of them are content to be alone, they often prefer to spend time with friends. Their time together may range from playing video games together to going to the movies.

Key Milestones

  • Show more concern about their future
  • Exhibit more defined work habits
  • Better able to explain the reasons for their choices

Parenting Tip

Show an interest in your teen’s activities. Step inside your teen’s world to learn about his favorite video games or to talk about the sports he enjoys. Your teen will appreciate your interest in learning about the things he enjoys.

Other Milestones

For many teens, 15 is the age where they get to take driver’s education. Obtaining a learner’s permit can be a big deal. And of course, it’s a big responsibility.

Make sure your teen is ready to handle the rules of the road before allowing him to drive a vehicle. If he can’t be responsible when it comes to chores or homework, he may be showing you he’s not yet ready to handle the responsibility of driving a car.

Not all 15-year-olds are ready to drive. So think carefully about whether your child is emotionally and socially mature enough to get behind the wheel.

When to Be Concerned

Pay attention to any changes in your teen’s mood or behavior. Difficulty sleeping, refusal to attend school, changes in appetite, or loss of interest in activities can be signs of a mental health issue.

Talk to your teen about her mood. Ask if she has ever experienced suicidal thoughts, particularly if she seems sad or depressed. Let her know you care about her and get professional help if she says she has been thinking about suicide.

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 1-800-273-8255 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

If you are concerned about your teen's development, talk to the doctor. If your child's doctor has concerns, your child may be referred to a mental health provider for further evaluation.

A Word From Verywell

Fifteen can be a big year for teens. You’re likely to see a big difference between your child’s 15th birthday and his 16th birthday.

And while you might be thinking he’s not ready for the rigors of the real world, keep in mind you’ve two years to prepare him for life after high school. Pay attention to the skill deficits that you see and proactively teach him strategies that will serve him well in his adult life.

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