The Highest IQ everwas William James Sidis, with an IQ score of around 250-300. He was an American
child prodigy with exceptional mathematical and linguistic abilities and was
fluent in multiple languages by the age of six. However, it's important to note
that IQ tests have limitations and there is an ongoing debate about their
reliability and validity in accurately measuring intelligence. Additionally,
there have been instances of people claiming to have higher IQ scores, but
their claims are often not independently verified.