How To Write Siblings

(This is a republished version of a guide I wrote on Tumblr a while ago that many people seemed to write. I’m posting it here for the benefit of the wider blogging community and for ease of searching because tumblr’s tagging system is notoriously trash.)

There are a few key aspects of the family dynamic you’ll want to keep in mind that will influence how the different relationships form! Siblings can have such a complex relationship that becomes fascinating to see in larger families: they can be best friends and worst enemies, and it’s a criminally underrated dynamic in fiction. Speaking as someone with 4 younger siblings, I’m here today to show you how to build accurate and compelling relationships for your characters.

Parental Roles:

(I’m using the term “parent” loosely, since it may vary depending on the story, but “legal guardian” sounded weird. Y’know what I mean)

Good parents will encourage mutually respectful relationships between their kids, avoid playing favorites, and work to settle bickering quickly and fairly. Siblings might get on each other’s nerves, but they’ll also be friends and whacky in-jokes abound.

Poor parents will either create an incredibly tight bond between siblings (to compensate for the lack of a reliable/safe adult support structure) or will drive siblings apart (probably by playing favorites, creating a bitter rivalry).

Another thing to consider is if both a mother and father figure are present. Kids being raised by a single parent or a grandparent will have a different dynamic than if both were around. Divorce or parental death can be a major traumatic early life event, and will affect how each child relates to their parent and to each other. I can’t really speak to this because I didn’t grow up in a separated family, but research by reading first-hand experiences. If the kids are orphans, or both parents are neglectful, a sibling might step up into the parenting role, creating a complex, co-dependent relationship.

Birth Order:

People will argue about this for aaaaagggess, but broadly speaking, the following personality traits are accurate:

Oldest/Oldest available (when the actual eldest isn’t around)/Oldest Daughter (when the older brothers are useless around the house):

• Strengths: organized, responsible, leader, probably half-decent at babysitting, cooking, and cleaning, may be a peacemaker between younger siblings.
• Weaknesses: bossy/opinionated, default center of attention OR invisible depending on the situation, may bully younger siblings
• With great privilege comes great responsibility

Middle (depending on place in the middle and age gaps, may lean more towards oldest/youngest behaviors in the family dynamic):

• Strengths: flexible, independent, more laid-back attitude, probably makes friends outside of the family easily
• Weaknesses: flighty, deliberately annoying, might feel inadequate or looked over in an older sibling’s “shadow”

Youngest:

• Strengths: “Go-get-em” attitude. They want to run with the older kids, and parents are too exhausted to stop them, so they learn a lot young. If the eldest could stay at home alone overnight at 16, the youngest is probably doing that at 14. Confident. The other default center of attention.
• Weaknesses: Tag-along, loud/obnoxious, used to getting their way.

When someone only has one sibling, it’s only the oldest/youngest dynamic, and it’s more likely for both to act independently. The parent’s attention isn’t split so many ways, like it would be in a large family, so carefully consider all the interactions and personalities and how they would affect the dynamic between the two. Specifically, if there’s a large age gap, they may function more like only children that live in the same house.

When you have a large family, pretty much everything in your life rotates around the family’s schedule. When are your parents available to take you to X event? Do you have to be present at Y event, who’s babysitting tonight? Each person has a defined role within the family and the relationships reflect that. More people = more chores to be done around the house and everyone would be expected to pitch in, though the elder siblings might share more of the work.

Shared Life Experiences:

How much time did they spend together growing up, and was that a positive or negative experience? Did their family experience a traumatic event? (probably in the protagonist backstory). How did they react and support each other through that? If there’s common ground, they might not talk about it because nothing needs to be said: they lived through it together. Would they hold grudges for old fights, or keep score or favors? What fond memories can they bond over?

Personality Dynamics/Clashes:

Depending on how you built your characters from the above questions, this can be a highly story-specific question to answer, but I’m just going to throw some generic dynamic ideas together inspired by my own siblings and stories:

• Oldest and 2nd Oldest sisters are mistaken as twins because they’re on the same mental wavelength 80% of the time. Lots of affectionate exasperation and mutual complaining/info dumping.
• Middle was the youngest for years until a younger sibling was born. Finds themselves caught between youngest “immaturity” and new expectations to be a good example of an older sibling.
• Two middle kids (2 years apart) bicker as small children but grow into being chill friends as teenagers once they both mature a little.
• Younger middle has different favored older siblings to go to for different problems when they can’t get mom or dad’s attention (asking oldest for help with school, older middle for help with friends, etc.)
• The impartial sibiling mediating arguments between overly concerned but justifiably frustrated parents and overly defensive but justifiably irritated sibling.
• Parents mediating arguments between overly concerned but justifiably frustrated older sibling and overly defensive but justifiably irritated younger sibling.
• Younger middle and youngest siblings being absolute agents of chaos together, and that insanity factor growing exponentially for each added person involved.
• The house is just TOO NOISY with all of this chatter, you’re banished outside until dinner time. Go play.
• The dynamic of: “oh my gosh they’re such a dumbass, but I love them too much to let them get away with this bad decision.
• Protective of each other against outsiders, even if they bicker a lot: “The only one allowed to punch my sibling is me.”
• Complaining with each other about their parents
• So many dumb in-jokes

Communication

If you’re writing a large family, communication is SUPER important. (communication is always important, but especially when there’s a lot of people in the mix). It’s likely the parents have some sort of tracking system in place so they can keep tabs on where their kids are – not to be controlling (though that’s possible if the parents are especially authoritative) but practically, to coordinate rides, and tell when people are going to be home, and figure out what time is dinner going to be (if they eat together), and who’s in the area to do errands, and to check if the kid got to the place safely.

The kids will also learn patience, because they might have to wait around their school for an hour until someone can pick them up. Middle and younger kids are more likely to find friends to catch a ride, whereas oldest kids might just opt to sit in the cafeteria and get ahead on homework, for example. Any older sibling will inevitably help with taxi duties.

In modern settings, that could be a location sharing app or a groupchat where parents say “text us when you get to school!”, or in fantasy settings you could worldbuild a different solution that accomplishes the same goal. The Weasley’s Clock is a great example of this, but you might also have synchronized charms or beacon bracelets or something else that works within your world!

Culture

How does the world treat families and sibling relationships? Do people live in generational households, growing up with dozens of cousins as pseudo-siblings? How much are children expected to respect and defer to their elders, and would you ever find the oldest sibling play wrestling with their baby brother? What kind of coming of age rituals might affect how older or younger siblings are perceived? Do you maintain ties to your family throughout adulthood or are found families common and accepted by law? Family is the most fundamental building block of a society, so once you design how that dynamic works, it can inform other aspects of your world’s philosophy and cultural practices.

I hope this helped you develop the families in your WIP! Before you go, I’d love some feedback on the site and how it’s working for you. Please take a minute to fill out my form and let me know how I can improve. If you feel so generously inclined, you can support my writing by leaving me a tip on my Kofi or donating using the secure box below. Until next time, thanks for reading and happy writing! 🙂