The firm, which brands include Marmite and Pot Noodle, fired a warning shot at the technology firms amid claims they fail to counter fake news and allow their platforms to “breed division”.
The company is expected to lay out its plans at the Interactive Advertising Bureau’s Annual Leadership Meeting in California on Monday.
Its chief marketing officer Keith Weed is to raise concerns over the social media and tech firms’ becoming platforms for the spread of illegal and extremist content.
"We cannot continue to prop up a digital supply chain, one that delivers over a quarter of our advertising to our consumers, which at times is little better than a swamp in terms of its transparency," Mr Weed will say, according to a speech prepared for the event.
"Fake news, racism, sexism, terrorists spreading messages of hate, toxic content directed at children - parts of the internet we have ended up with is a million miles from where we thought it would take us.
"It is in the digital media industry's interest to listen and act on this. Before viewers stop viewing, advertisers stop advertising and publishers stop publishing."
The Standard has approached Google and Facebook for comment.
Mr Weed has already met with a raft of Unilever's digital partners including Facebook, Google, Twitter, Snap and Amazon, to stress that Unilever "do not want to advertise on platforms which do not make a positive contribution to society".
There are also concerns over how illegal content is impacting public perception of brands.
"Consumers don't care about third party verification. They do care about fraudulent practice, fake news, and Russians influencing the US election.
"They don't care about good value for advertisers. But they do care when they see their brands being placed next to ads funding terror, or exploiting children," Mr Weed will say.
The Anglo-Dutch group - which is behind Dove, Marmite and Ben & Jerry's ice cream - will confirm that it will not invest in "platforms or environments" that breed division, or promote anger or hate, or fail to protect children.
Mr Weed will also confirm that the company will only partner with organisations that it believes are creating "better digital infrastructure".
"So I am not interested in issuing ultimatums or turning my face while I demand others sort this out.
"I prefer to be part of the solution," Unilever's CMO will say.
Unilever cited research showing that trust in social media has hit a new low as a result of failed action over misleading or unlawful content, and said that while 2017 was the year of mobile video and voice, 2018 will either be the "year of trust" or the "year of techlash", where the world will turn on tech giants.
"This is a deep and systematic issue. An issue of trust that fundamentally threatens to undermine the relationship between consumers and brands.
"Brands have to play their role in resolving it," Mr Weed's speech will say, highlighting its influence as one of the world's largest advertisers.
"No longer can we stand to one side or remain at arm's length just because issues in the supply chain do not affect us directly... To remain relevant, and trusted by consumers, brands have to take the lead."
Liberum analyst Ian Whittaker said Unilever's stance provides an opportunity for free to air broadcasters in the UK who may retain and gain more advertising as a result.
"It is clear advertisers are becoming increasingly wary of online's quality (P&G has also been cutting its digital ad spending without any impact on growth) and so are unlikely to shift money aggressively from TV to online as these concerns mount," he said in a research note, co-authored by Liberum analyst Annick Maas.
"There is a big opportunity for the broadcasters to take a share of the online video advertising market, where their share is a lot smaller than in TV advertising," he added.
"Moreover, these revenues tend to be high margin ... with price rates significantly ahead of linear TV.
"Online could thus be a big driver of future profit growth (for free to air broadcasters)," Mr Whittaker said.
Additional reporting from the Press Association.