OnePlus or OnePlus Technology (Shenzhen) Co., Ltd is a Chinese smartphone manufacturer based in China. The company was founded by two former Oppo guys Pete Lau and Carl Pei in December 2013.

Oppo began with an aim to give smartphone buyers a flagship phone with no flagship price. OnePlus 1 was an example of this. OnePlus came with an exclusive licensing agreement with Cyanogen Inc. to launch OnePlus phone with this popular custom ROM. Later after some issues, they developed their own OxygenOS that became really successful. 

With time, they also gradually increased the price of their smartphones to charge flagship price for flagship phones.