It’s about mid-way through summer break for most kids. School will be starting back up before you know it. Many kids spend more time with their siblings during the summer than they do during the school year. This time spent together inevitably leads to more bickering, more butting heads, more annoyances between siblings.

There are many reasons siblings fight. Here are a few of the factors that influence sibling rivalry.

Developmental level and age

  • Kids go through different stages of development. Every child is different, but generally speaking there are some commonalities in how children of different age groups will relate to others and how they will view their world.
  • EXAMPLE: Toddlers are pursuing independence while also learning about having their own possessions (think “mine, mine, mine”). School-aged kids (about 5 to 10 year olds) are continuing to establish their independence but also often view their lives in terms of what is fair. If a toddler has a school-aged sibling there can be sibling rivalry when the way in which each child naturally functions contradicts the other. If a toddler wants to assert his willpower and take ownership of his brother’s blocks but the older brother doesn’t think it’s fair that the toddler gets to use his toys, sibling rivalry can rise.


  • Temperament is the innate traits a child has from birth. For instance, some babies tend to be more easy-going, some have difficulty adjusting to new situations, and others are very active. This temperament sticks with a person throughout their life. Temperament is then influenced by a person’s experiences and environment to create personality.
  • EXAMPLE: When a laid back child has a sibling who is hyperactive and very social, sibling rivalry can increase if they have a personality clash that causes them to bother one another.

Problem-Solving and Emotion Regulation skills

  • Being able to effectively solve one’s own problems is necessary for being able to take care of one’s own needs and preferences while also being respectful toward others. Regulating one’s own emotions is important for many reasons including having healthy relationships with siblings, peers, and others.
  • EXAMPLE: A 7 year old child who lacks strong emotion regulation skills may become quick to act aggressively when his 4 year old sister takes some of his toys or even when things just don’t go his way. This child will need to improve on his emotion regulation skills to reduce the sibling rivalry with his sister.

Behaviors modeled by adults

  • Parents are an essential, but certainly not the only, part of teaching (by modeling and discussing) appropriate values and behaviors to their children.
  • EXAMPLE: If parents tend to react calmly to situations that bother them or if, on the other hand, parents tend to react quickly and aggressively to things that make them mad, children will tend to behave in similar ways. Of course, this is not to say that parents have to be perfect or that you can’t make a mistake. Kids will likely still need helping learning to manage their relationships with their siblings even if their parent is the nicest person in the world.

Cultural and societal influences

  • The environment that children grow up in influences the way in which they internalize values regarding relationships and conflicts.
  • EXAMPLE: The Eastern and Western cultures vary (generally speaking) on the way in which the culture emphasizes individualism (prioritizing of one’s own needs) versus collectivism (thinking more of what is good for the larger group). Additionally, the influences of various communities, such as inner city lower socioeconomic status neighborhoods with a high crime rate compared to a high socioeconomic status suburban area with many community resources (this is just an example and by no means am I stereotyping any of these terms) will differ on the messages that children pick up on which will impact how they relate to others including their siblings. Safety, security, trust, generosity, and other concepts can be influenced by cultural and societal factors.

These are some of the reasons why siblings fight so much. An upcoming blog post will address how parents can deal with their kids’ sibling rivalry in effective ways.

(Image by Life Mental Health)