The two will work closely on category development, supply chain and fulfilment, data and marketing, social commerce and talent development as they seek to drive new growth in online sales and consumer insights for both companies.
The move marks the next step in a partnership that recently saw the launch of an exclusive Unilever store on Lazada Singapore where shoppers can buy Unilever brands at the click of a button.
"E-commerce is the fastest growing channel in Southeast Asia making it vital for us to find innovative ways to address the needs of our consumers," said Pier Luigi Sigismondi, President, Unilever - Southeast Asia and Australasia.
He told CNBC that online tailored marketing had helped the business generate higher online sales in March this year than had been achieved over the whole of 2016.
"This [partnership] will allow us to grow our online sales by three times compared to what we saw in 2015 and 2016," he added.
But Unilever is not solely focused on online sales, as Sigismondi explained that the tie-up will enable it to test new products before deciding whether to make them available offline. At the same time this allows it to offer exclusive products to Lazada shoppers.
Lazada, meanwhile, sees the partnership as a "game changer", according to CEO Maximilian Bittner, who said "it endorses our one-stop platform strategy to support the online development of top brands like Unilever".
With Chinese internet giant Alibaba having taken a $1bn majority stake in Lazada this time last year, and observers expecting Southeast Asia to be the next target market for Amazon, the scene is set for another clash between the two e-commerce titans, but Bittner is unperturbed by the prospect.
"It's very hard for me to worry about someone who has not actually entered the market yet," he said. "I think once they're here, we can start worrying about them."
Data sourced from Unilever, CNBC; additional content by WARC staff