Behaviour or Behavior | Meaning, Spelling & Examples

Behaviour and behavior are two different spellings of the noun referring to the way a person, animal, other organism, or machine acts or functions. It’s related to the verb ‘behave’ meaning ‘conduct oneself’ or ‘act’.

The spelling varies depending on whether you’re using UK or US English:

  • In UK English, ‘behaviour’ (with a ‘u’) is standard.
  • In US English, ‘behavior’ (with no ‘u’) is the correct spelling.
    Examples: Behaviour and behavior in a sentence
    The school does not tolerate bullying or other forms of anti-social behaviour/behavior.

    Ever since he broke the vase, Gus has been on his best behaviour/behavior.

    Jordan’s research focuses on the relationship between empathy and criminal behaviour/behavior.

    As of yet, little is known about the behaviour/behavior of the virus.

    Many words that end in ‘-our’ in UK English end in ‘-or’ in US English. Some other common examples include ‘favour/favor‘, ‘colour/color‘, ‘honour/honor‘, and ‘flavour/flavor’.

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    Behavioural vs behavioral

    The regional spelling distinction carries over to related forms of the words, including the adjective ‘behavioural/behavioral’ and the adverb ‘behaviourally/behaviorally’.

    • In UK English, ‘behavioural’ and ‘behaviourally’ are correct.
    • In US English, ‘behavioral’ and ‘behaviorally’ are standard.
        Examples: Other forms of ‘behaviour/behavior’ in a sentence
        Kayla is studying to become a behavioural/behavioral psychologist.

        Research has found that human infants and ape infants are behaviourally/behaviorally similar.

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        Best behaviour or best behavior

        Best behaviour/best behavior is part of the expression ‘be on your best behaviour/behavior’, meaning ‘behave very well’. The possessive determiner used in the expression varies depending on the person being referred to. The spelling distinction also applies to this phrase.

            Examples: ‘Best behaviour/best behavior’ in a sentence
            The principal has asked students to be on their best behaviour/best behavior during the school inspection.

            Anthony is on his best behaviour/best behavior because he has his employee review next week.

            Other interesting language articles

            If you want to know more about commonly confused words, definitions, common mistakes, and differences between US and UK spellings, make sure to check out some of our other language articles with explanations, examples, and quizzes.

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            Ryan, E. (2023, March 14). Behaviour or Behavior | Meaning, Spelling & Examples. Scribbr. Retrieved 9 April 2024, from

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            Eoghan Ryan

            Eoghan has a lot of experience with theses and dissertations at bachelor's, MA, and PhD level. He has taught university English courses, helping students to improve their research and writing.