Walia joined the company in April last year.
"Sumit Walia has decided to take the next step in his professional career and part ways with OPPO. We thank Sumit for his relentless service and leadership at OPPO India and wish him all the best for his future endeavours," the company said in a statement on Saturday.
Walia worked with Samsung before joining OPPO.
He oversaw the June launch of flagship OPPO Find X2 and Find X2 Pro 5G smartphones with 120Hz refresh rate display and 65W SuperVOOC 2.0 flash charging support in the country.
Under his leadership, OPPO shipments grew 83 per cent in Q1 2020, due to a surge in demand for its budget segment devices, A5 2020 and A5s, as well as a good performance for A31 and A9 2020 in the offline segment, according to Counterpoint Research.
Before the Covid-19 triggered nationwide lockdown, Walia had told IANS that OPPO aims to manufacture 100 million handsets in India by the end of 2020, along with an aggressive retail push to let more people experience flagship devices.
The months-long lockdown amid frequent disruptions have affected the smartphones brand in the country and the industry hopes for a rebound in the festive quarter.