Parallel Structure in English: A Complete Guide

Learn what parallelism in writing is, its importance in English, and how you can use it for language development

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Parallel structure is about building clear, balanced sentences that make sense from start to finish. Also known as parallelism in writing, this essential grammar rule helps you express ideas smoothly while following consistent patterns.

You can use it when making a list, drawing a comparison, or joining two thoughts with “either…or.”

In this article, you’ll learn

What parallel structure means and why it matters
How to recognize and fix common errors
Real-life writing situations where parallelism makes a difference
How to build fluency through practice

By the end, you’ll be able to write with more clarity, rhythm and confidence. And if you’re ready to take your grammar further, Busuu’s smart learning tools are here to help you get there for free.

What is parallel structure?

Parallel structure is the repetition of a grammatical pattern to express related ideas with equal importance.

Take a look at this sentence:

I like swimming, biking and to run.

Something feels off, right? That’s because it breaks the rhythm of parallel structure by including two different types of word in the same list: the gerunds swimming and biking, and the infinitive to run.

Using parallelism makes your sentences flow naturally, keeps your meaning clear and helps your readers follow your ideas without stumbling.

Parallel structure ensures that when you list multiple activities, qualities or ideas, each item matches the others in grammatical form.

Here are two more examples:

Incorrect: He wants to
travel
,
exploring
new foods and
learn
languages.
Correct: He wants to
travel
,
explore
new foods and
learn
languages.
Incorrect: The team will
plan
,
executing
and
review
the project.
Correct: The team will
plan
,
execute
and
review
the project.

Meet parallelism in writing

Parallelism in writing simply means keeping your ideas in the same form so your sentences are clear and easy to follow. Writers use it in lists, comparisons and paired ideas to give equal weight to each point.

If you start a list with verbs, all items should be verbs. If you begin with adjectives, the rest should be adjectives too. When your sentence keeps the same structure, you and your readers understand your point immediately and don’t get tripped up by awkward phrasing.

Parallel vs faulty parallel structure

Correct parallel structure	Faulty parallel structure	Why it’s wrong
I like swimming , biking and running .	I like swimming , biking and to run .	Mixed verb forms (gerund & infinitive) disrupt the rhythm.
She is smart , kind and funny .	She is smart , kind and has a good sense of humor .	Adjectives mixed with phrases create imbalance.
He wanted to study , to work and to travel .	He wanted to study , working and travel .	Inconsistent verb forms break the flow.
They must either accept the offer or decline it .	They must either accept the offer or declining it .	Incorrect form with “ either…or .”

Mini tip: Whenever you write a list or comparison, read it aloud. If it doesn’t sound smooth, check for parallelism.

Why is parallelism in writing important?

Parallelism strengthens sentence rhythm and makes your writing easier to read. This makes your message land faster and stick longer.

Even small mismatches can make a sentence feel messy or uneven. Parallel structure gives each idea equal importance so your reader knows exactly what you mean.

But how can it improve your writing skills?

It clarifies meaning and improves readability. Sentences that use parallel structure make your ideas stand out neatly. Readers don’t have to pause or guess how the pieces fit together.
It adds rhythm and fluency to writing. Parallelism makes your sentences move smoothly, like walking instead of tripping over your own words. Balanced structure keeps your writing lively and easy to follow.
It shows equal weight for your ideas. Using the same form signals that every point matters the same. This comes in handy in instructions, essays and anything you want to sound logical and fair.
It matters for exams and professional writing. Tests, reports and emails often check how clear your sentences are. Parallelism proves that you know how to organize your thoughts, making your writing look neat and professional.

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Grammar rules for parallel structure

Parallel structure has simple rules, and knowing them will help you line up verbs, nouns, phrases and comparisons so your sentences stay smooth and readable.

Understanding this makes lists, series and paired ideas look tidy and professional, and it avoids the awkward stumbles that happen when forms don’t match.

In the next sections, we’ll break down the main areas where parallel structure matters most, including lists and series, comparisons and correlative conjunctions. You’ll see exactly what works, what doesn’t and why.

But first, look at the table below for a summary of basic parallelism rules.

Parallel structure grammatical rules

Use case	Rule	Correct example	Incorrect example
Lists and series	Use the same form for each item (noun, verb, phrase and so on).	She enjoys reading , writing and drawing .	She enjoys reading , to write and drawing .
Comparisons	Keep both sides of a comparison parallel in form.	He is smarter than she is .	He is smarter than her .
Correlative conjunctions	Use the same structure after each part of the pair.	Not only did he speak , but he also listened .	Not only did he speak , but also listening .
Verb forms	Use consistent verb tense and structure.	They planned , organized and executed the event.	They planned , organizing and executed the event.
Phrases and clauses	Match the structure of each phrase or clause.	The guide was clear , concise and helpful .	The guide was clear , giving clarity and helpful .

Next, let’s explore these rules a bit further.

Parallel structure in lists and series

When you write a list, all items should share the same grammatical form. Nouns line up with nouns, verbs with verbs, and phrases with phrases.

Here’s what you must consider:

1. Use the same part of speech for all items

Incorrect: The manager was
firm
,
fairness
and
consistent
.
Correct: The manager was
firm
,
fair
and
consistent
.

Keep the form consistent. If one item is a noun, the others should match. If one is an adjective, they should all be adjectives. This keeps your list balanced and easy to read.

2. Avoid mixing gerunds and infinitives

Incorrect: He likes
swimming
,
to run
and
biking
.
Correct: He likes
swimming
,
running
and
biking
.

Think of gerunds and infinitives as different dance moves. If one is jumping, don’t suddenly start sliding. Stick to one rhythm.

3. Compare each item in the list

Incorrect: The team will
plan
,
executing
and
review
the project.
Correct: The team will
plan
,
execute
and
review
the project.
Incorrect: The plan includes
analyzing data
,
creating slides
and
to give presentations
.
Correct: The plan includes
analyzing data
,
creating slides
and
giving presentations
.

Compare each item side by side. If one looks “off,” it probably is. This is the fastest way to catch mismatches.

Parallel structure in comparisons

Comparisons can trip you up fast if the forms don’t match. When you use words like than or as, both sides of the comparison need to be addressed in the same way.

If one side shows up in a tuxedo and the other in flip-flops, the sentence stumbles.

Examples

Incorrect: She likes
swimming
more than
to run
.
Correct: She likes
swimming
more than
running
.
Incorrect:
My brother
is smarter than
to study hard
.
Correct:
My brother
is smarter than
my cousin
.

When making comparisons, check if you’re really comparing like with like. Ask yourself, “Are both sides in the same grammatical style (verb with verb, noun with noun)?”

If not, your comparison will feel uneven.

Parallel structure with correlative conjunctions

Correlative conjunctions

work in pairs, and both sides of the sentence must mirror each other.

If the first element is a verb, the second should also be a verb. If it’s a noun, the second part should be, too.

Messing this up makes the sentence clunky and harder to follow.

Examples:

Incorrect: He likes both
to swim
and
running
.
Correct: He likes both
to swim
and
to run
.
Incorrect: She is interested not only
in the project
but also
working with the team
.
Correct: She is interested not only
in the project
but also
in the team
.
Incorrect: They promised either
a bonus
or
working from home
.
Correct: They promised either
a bonus
or
a chance to work from home
.
Incorrect: He would rather
play video games
than
a nap
.
Correct: He would rather
play video games
than
take a nap
.

Think of correlative conjunctions as two sides of a scale. Whatever you put on one side, you must balance on the other. If you drop in a noun first, don’t throw a verb on the other side.

Common parallel structure mistakes

Parallel structure errors are extremely common in writing, and most of them happen because elements don’t “line up” in form or logic.

Below are the most frequent parallelism mistakes to avoid.

Shifting categories – Mixing unrelated ideas (skills, objects, actions) in the same list.
Uneven detail – Including a list item that is far longer or more specific than the others.
Redundant verb structures – Repeating the same verb for each item when one shared verb would be more concise.
Mismatched tone – Switching between formal and informal words in a list.
Overweight elements – Overloading one idea with modifiers or explanations.
Inconsistent direction – Combining verbs or phrases that pull in different directions.
Asymmetrical comparisons – Comparing two things that do not match in form and intent.

Mini checklist for spotting parallel structure errors

Use this quick editing checklist when reviewing your sentences:

Are all items in a list in the same grammatical form?
Are verb forms (gerunds and infinitives) consistent throughout?
Do singulars and plurals match?
Do comparisons use the same type of expression on both sides?
Do correlative conjunctions balance properly?

Ready to move beyond parallel structure?

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