17-Year-Old Child Development Milestones

Your child’s growth and development at age 17.

While many 17-year-olds are looking forward to a bright future beyond high school, others are terrified about entering the adult world.

And for parents, raising a 17-year-old can be a little scary. Have you taught your teen everything he's going to need to know to become a responsible adult? It's important to evaluate his development and assist him accordingly before he enters into the real world.

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

Physical Development

Most males and females are fully developed by their 17th birthdays. They’ve completed puberty and reached their full height.

Boys may continue to develop muscles. They may also grow more facial hair and underarm hair. Their voices may continue to deepen as well.

Body image issues are common at this age as some teens aren’t pleased with the physical changes they’ve endured. Acne can also be common.

Key Milestones

  • Have reached their full height
  • Have completed puberty
  • Boys may continue to develop muscles

Parenting Tip

Talk to your teen about good health, rather than appearance. Keep the focus on eating nutritious food, rather than dieting or bulking up.

Emotional Development

Turning 17 represents an interesting fork in the road for many teens. Some of them take off on a smooth path toward adulthood. They become increasingly responsible and they’re eager to become independent.

Others, however, are terrified of the realities of pending adulthood. Some of them seem lost and confused over the future. They may struggle to show responsibility with their homework, chores, and daily responsibilities and may feel fearful about becoming an adult.

For the most part, a 17-year-old teen's moods are calmer than they were in earlier teen years. This is due to fewer hormonal shifts and an increased sense of control.

That doesn't mean your teen won't struggle with his emotions when he faces a big problem. Whether he's dealing with a broken heart or a college rejection letter, many 17-year-olds are dealing with adult-sized problems for the first time.

Most 17-year-olds are goal-oriented. They're beginning to imagine what type of life they want to create beyond high school.

Key Milestones

  • Show more independence from parents
  • Have a deeper capacity for developing more intimate relationships
  • Take fewer risks

Parenting Tip

Allowing her to drive a car, get a job, and stay home alone for the night are just a few steps toward becoming an adult. It's important to rein your child in, however, if she is making poor choices.

Social Development

Most 17-year-olds form strong relationships. They develop close friendships and become less likely to move back and forth between cliques.

Most 17-year-olds find that it’s important to be dependable. When they make a promise to their friends, they want to honor their commitments.

Your teen may spend the vast majority of her free time with friends and when she’s home, she may prefer to be in her room by herself.

The parent/teen relationship may shift a little during this age. For some, that may mean growing apart as a teen gains independence, but for others, teens may actually grow closer as their desire to be rebellious phase fades away.

Key Milestones

  • Search for intimacy
  • Want adult leadership roles
  • Able to make and keep commitments

Parenting Tip

Establish clear rules about dating. Talk often about healthy relationships, safe sex, and dating.

Cognitive Development

By age 17, most teens have good organizational skills. Many teens are able to successfully juggle extracurricular activities, part-time jobs, and school work.

Although many 17-year-olds think they’re adults, their brains still aren’t yet fully developed. So while they may have skills to regulate their impulses, they may still behave recklessly at times.

Most 17-year-olds are thinking about the future. They begin to establish more concrete plans for life after high school.

Fluid intelligence is reached around this age which means 17-year-olds have an improved ability to cope with new problems and situations.

Speech & Language

Most 17-year-olds can communicate like adults. Although they may not ask for clarification or speak up with they don’t understand a word or the meaning of a phrase.

Slang is common among teens. Slang words may have more meaning than formal language at this age.

Some 17-year-olds still struggle to understand double negatives. And although their attention spans are improved, it’s common for them to lose track of long, complex questions.


Play to a 17-year-old might involve going to a restaurant with a friend or it could include engaging in a hobby with a friend. Many 17-year-olds engage in similar leisure activities as adults. Most of them have developed hobbies and interests that allow them to relax.

Key Milestones

  • Can communicate like an adult
  • Likely uses slang
  • Improved ability to cope with new problems and different situations

Parenting Tip

Encourage your 17-year-old to read for fun. Reading can help continue to build a teen’s vocabulary while also improving their writing skills.

Other Milestones

Seventeen-year-olds may be experiencing a variety of things for the first time. Some of them are getting a driver’s license and a car. Others are getting part-time jobs.

Others may be engaging in some riskier behavior. Unprotected sex, drugs, and alcohol may be a few things your teen wants to try.

And for some teens, age 17 is the first time they experience a serious romantic relationship and perhaps even their first heartbreak. Many of them may struggle to cope with these adult-like issues.

When to Be Concerned

If the thought of sending your 17-year-old out into the real world within the next year terrifies you, you're not alone. Many parents can't imagine their teen navigating the adult world independently.

But, often, there's a lot of growth between 17 and 18 years old. And within that year, teens become ready to enter college or the working world.

If your teen seems especially ill-equipped for the realities of adulthood, you might want to talk to your child’s doctor.

You should also be concerned if you see major changes in your teen’s mood or behavior. A decline in grades, changes in sleep habits, or change in weight or appetite are just a few symptoms that could indicate a mental health issue or other underlying problem.

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Article Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Teenagers (15-17 years of age). 2019.

  2. Coyle TR, Pillow DR, Snyder AC, Kochunov P. Processing speed mediates the development of general intelligence (g) in adolescence. Psychol Sci. 2011;22(10):1265-9. doi:10.1177/0956797611418243

  3. University of Pennsylvania, Penn Medicine. 6 Facts Parents Should Know about Mental Illness in Teens. 2018.

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