The new device will be unveiled next week on 16 May in London. But before then, OnePlus fans have the change to trade in their old device to make way for the OnePlus 6.
If you live in the UK, you can trade in a OnePlus 3 smartphone or newer until the end of May via the phone maker's official site . In return for an old phone, you will receive a voucher up to £205 to put towards your new smartphone.
But until then, here's all the rumours and leaks that have come out so far.
OnePlus 6: what will it look like?
Design-wise, the OnePlus 6 is thought to have a larger, longer screen than previous iterations.
As well, that means it is going to be copying the iPhone X with a notch at the top of the screen, moving away from the thin bezels the OnePlus 5T.
Some new leaked images from GSMArena show the new phone compared to the latest iPhone and the two devices look pretty similar.
Following a leaked spec sheet, it appears the new phone is going to have a 6.28 inch AMOLED display with 2280 x 1080 resolution.
That’s pretty big.