Police are appealing for witnesses after the crash on the B3035 at the junction with Corhampton Lane at 11.46am this morning.
The collision involved a white Citreon Relay, a yellow Fiat Panda, a grey VW Polo, and a blue Suzuki motorcycle.
The rider of the motorcycle, a 71-year-old man, was pronounced dead at the scene.
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His family have been informed and are being supported by specialist officers.
Police are hoping that someone may have dash cam footage that could assist their investigation, according to a spokesman from Hampshire Constabulary.
He said: ‘Enquiries are being conducted into the exact cause of the collision, and we are keen to speak with any witnesses who may help our investigation.’
Anyone with information is asked to phone 101 and quote the reference number 44210224948.