Behaviour or behavior?

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Behavior” is mainly an American spelling of the noun behaviour, while both American and British English spell “behave” the same.

What is the difference between behaviour and behavior?

Behaviour” and “behavior” are two spellings of the same word. Behavior is an American variant, while countries that use British English prefer behaviour. Canadian English can incorporate both spelling variations, but native speakers largely favor “behaviour” over the American variation.

The distinction applies to related terms, as well

Word derivatives of behavior/behaviour follow the same spelling patterns between American and British English. Examples include:

  • Behaviors / behaviours (plural noun)
  • Behavioral  / behavioural (adjective)
  • Behaviorally / behaviourally (adverb)
  • Behaviorism / behaviourism (noun)
  • Behaviorist(s) / behaviourist(s) (noun)

Are there related words with the same spelling?

The verb “behave” is the only related term that shares the same spelling for British and American English. 

What does behavior mean?

The word behavior (also “behaviour”) is a mass noun that references: 

  1. How a person, animal, or object behaves or conducts themselves toward others, a specific stimulus, or under particular conditions, or;
  2. The way a machine or “natural phenomena” functions.

Example sentences:

  • “Logic and personal experience cannot always explain the psychology of human behavior.”
  • “There is specific behavior we cannot tolerate.”
  • “Future research will examine the behavior of a male animal.”
  • “Social distancing is a form of normative behavior during a pandemic.”

The mass noun derives from the verb “behave,” meaning ‘to act, conduct, work, or function in a specified way.’ This is why we see “behavior” in the phrase “be on one’s best behavior, which instructs someone to “behave well in a social situation or when being observed” (esp. “in accordance with the accepted normals of a society or group”). 

For example,

  • “Classroom learners are expected to be on their best behavior, which includes timely attendance, raising one’s hand to speak, and displaying good manners.”


Action, bearing, conduct, demeanor, deportment, etiquette, functioning, operation, performance, reaction, response, running, working.

Etymology of behavior and behaviour

The spelling of “behavior” emerged in the 15th century from Middle English behavour through the verb behave (from Middle English behaven). 

According to The Oxford Dictionary of Word Histories, the be– of behaven meant ‘thoroughly’ while haven meant ‘have’ (from Old English habban). Altogether, behaven meant “to have or bear oneself in a particular way,” and corresponds with modern German sich behaban (also meaning behave) (Chantrell 50–149). 

The switch from behavour to behavior/behaviour follows the pattern of demeanour, an obsolete spelling of demeanor, which derived from Old French demener (‘to lead’) in the 15th century (149). Both “demeanor” and “behavour” are thought to have been influenced by Middle English ​​havour (also found as “haver,” “havior,” or even “haviour,” the dated form of ‘having’) (50). The noun havour derives from Old French avoir or aveir (‘to have’) via Latin habēre (‘to have’).  

How to use behavior vs. behaviour in a sentence?

First and foremost, if you’re writing for a North American audience, be sure to use behavior, not behaviour. The opposite is true for English audiences outside North America (and sometimes within Canada), where it’s standard to use behaviour, not behavior.

Secondly, behavior/behaviour is a mass noun (otherwise known as a “noncount noun” or “uncountable noun”), so it already references one or more “ways of conducting oneself.” Therefore, the correct way to use either spelling is without an -s- on the end.

Correct: “You must atone for your scandalous behavior.”

Incorrect: “You must atone for your scandalous behaviors.”

Published examples of behavior

  • “On the other side of the paradox lies quantum mechanics, the physics theory that explains the behavior of small particles.” — Space
  • “Fully understanding and anticipating your barriers and blocks to behavior change is the first step to creating the healthy life you want to live.” — Florida Today
  • “Most of the children received a mix of speech and occupational therapy and applied behavior analysis, the standard treatment for ASD.” — The Wall Street Journal
  • “But one thing that algorithms presumably cannot do, besides feel heartbreak, is formulate theories to explain human behavior or account for the varying blend of motives behind it.” — The New York Times

Published examples of behaviour

  • “Apple says that complaints about wobbly displays on its new iPad Mini are just showing normal behaviour for the tablet’s screens.” — The Independent
  • “… the research showed virtual tests could be used to accurately study the bird’s natural behaviour in the real world.” — The Guardian
  • “… ‘Evering Road’ looks back at his less than perfect behaviour as a boyfriend and his journey through the split.” — Clash Magazine
  • “… Singapore has put two autonomous robots on trial to detect bad behaviour such as flouting of COVID-19 safety measures, smoking in prohibited areas and the improper parking of bicycles…” — Reuters

When to use a plural form of behavior or behaviour?

When behavior/behaviour includes the letter -s-, it’s typically a specialized term for topics related to psychology or social science to list specific actions or tendencies prone to a condition, culture, society, environment, etc.

Example sentences:

  • “Problem behaviours were classified as either “internalizing” (depression and anxiety) or “externalizing” (aggression, attentional problems).” — Science Daily
  • “This survey dataset can aid researchers, policymakers, businesses, and government agencies in understanding both the extent of behavioral shifts and the likelihood that changes in behaviors will persist after COVID-19.” — Scientific Data

Additional reading

If you enjoy learning the subtle spelling differences between American and British English, be sure to check out similar lessons by The Word Counter, such as:

Test Yourself!

Test how well you understand the difference between behavior and behaviour with the following multiple-choice questions. 

  1. True or false?: The spelling of “behave” falls under British standardization and American standardization.
    1. True
    2. False
  2. The broader definition of behavior or behaviour includes the _______________________.
    1. Computed response of the system or being to various stimuli or inputs
    2. A specific response to a group of stimuli in a physical environment
    3. Way someone behaves in a particular situation to different things or circumstances
    4. All of the above
  3. Which of the following does not use the correct North American spelling?
    1. “Problem behaviors”
    2. “A behavior informatics perspective” 
    3. “Behavioral patterns”
    4. “Control one’s own behaviour”
  4. Which of the following does not use the correct British spelling?
    1. “Analyzing consumer behaviour”
    2. “Behave yourself”
    3. “Noting behavioral attributes.”
    4. “To honour human behaviour.”
  5. Native speakers from ____________ are more likely to use the spelling of behaviour than behavior.
    1. New Zealand
    2. England
    3. Australia
    4. All of the above
  6. Which of the following is neither a British or North American variant?
    1. Behaviorism
    2. Behavior(s)
    3. Behave
    4. Behaviorist(s)
  7. The modern spelling of behavior/behaviour stems most recently from ___________. 
    1. UK English
    2. Middle English behaven
    3. Middle English havior
    4. Old French havoir

Quiz Answers

  1. A
  2. D
  3. D
  4. C
  5. D
  6. C
  7. B


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Behave.” Lexico, Oxford University Press, 2021.

Behavior.” The American Heritage Dictionary of the English Language, 5th ed, Houghton Mifflin Harcourt Publishing Company, 2021. 

Behavior.” Cambridge Dictionary, Cambridge University Press, 2021.

Behavior.” Collins English Dictionary, HarperCollins Publishers, 2021.

Behavior.” Lexico, Oxford University Press, 2021.

Behavioral problems linked to cortisol levels: Study finds intervention needed as soon as behavioral problems appear.” Concordia University, Science Daily, 10 Feb 2011.

Chantrell, Glynnis, Ed. “Behave,” “Demeanor.” The Oxford Dictionary of Word Histories, Oxford University Press, 2002, pp. 50–142.

Chauhan, R.S., Bhagat-Conway, M.W., Capasso da Silva, D. et al. “A database of travel-related behaviors and attitudes before, during, and after COVID-19 in the United States.” Scientific Data,, 23 Sept 2021.

Carey, B. “Need a Hypothesis? This A.I. Has One.” The New York Times,, 24 Nov 2020.

Griffin, A. “Apple says new iPad Mini’s wobbly displays are ‘normal behaviour.'” The Independent,, 29 Sept 2021.

Have.” The American Heritage Dictionary of the English Language, 5th ed, Houghton Mifflin Harcourt Publishing Company, 2021. 

Hāvǒur n.” Middle English Compendium, University of Michigan Library, 2021. 

Potter, L. “Language tip of the week: behaviour.” Macmillan Dictionary Blog, Macmillan Dictionary, 2021.

Kramer, M. “Stephen Hawking’s New Black Hole Theory: Scientists Remain Unconvinced.” Space,, 28 Jan 2014.

Lin, C. “Singapore trials patrol robots to deter bad social behaviour.” Reuters,, 6 Sept 2021.

Lu, D. “New Zealand kea can use touchscreens but can’t distinguish between real and virtual worlds.” The Guardian,, 28 Sept 2021.

Reddy, S. “The Autism Diagnosis That Isn’t Always Permanent.” The Wall Street Journal,, 25 Mar 2019.

Ronsisvalle, M. “Change can be hard, messy and uncomfortable, but it’s not impossible.” Florida Today,, 28 Sept 2021.

Photo contributors: Thought Catalog (@thoughtcatalog) and Jonas Jacobsson (@jonasjacobsson) on Unsplash.