Belsize could refer to:
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Belsize Park – also known as 'Belsize' – a neighbourhood in London, the United Kingdom
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Belsize (ward), a ward named after Belsize Park, London
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Belsize, Hertfordshire, a hamlet in Hertfordshire
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Belsize architects, a firm of architects based in Belsize Park, London
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Belsize Motors, a former automobile-manufacturing firm based in Manchester
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