There is no definitive answer to this question as it is subjective and dependent on individual interpretation. However, we can look at some of the largest heads in the world to get an idea of who might have the biggest head.
One contender for the title of biggest head in the world is Robert Wadlow, also known as the Alton Giant. Wadlow was born in 1918 and suffered from gigantism, a condition that caused him to grow to an extraordinary height. At his tallest, he measured 2.72 metres (8 feet 11 inches) and weighed 222 kilograms (489 pounds). His hands were also exceptionally large, measuring 32.3 centimetres (12.75 inches) from the wrist to the tip of his middle finger. Wadlow's head was larger than average too, measuring 91 centimetres (36 inches) around
the brow and 63 centimetres (25 inches) from front to back.
Another person with an unusually large head is Yao Defen, a Chinese woman who held the Guinness World Record for tallest living female at her death in 2012. Yao stood at 2.33 metres (7 feet 8 inches) tall and weighed 159 kilograms (351 pounds). Her head circumference was an impressive 1 metre (39 inches).
It's difficult to say definitively who has the biggest head in the world as there are many people with abnormally large heads due to conditions like gigantism or acromegaly . However, based on these examples, it seems safe to say that there are some people out there with very big heads indeed!