The company is the first major publisher in the UK to use Quantcast Brand Lookalike targeting, which helps advertisers reach the exact consumer segments they want with impression-level targeting.
Quantcast claims Brand Lookalikes identifies the unique characteristics of an advertiser's target audience through predictive modelling, in order to find other consumers across the web that most closely match these profiles.
It adds that publishers can combine their premium content with audience targeting to better match their inventory to an advertiser's audience.
Tim Gentry, revenue director at Guardian News & Media, said: "Building brands effectively has always been about communicating with the right people in the right context, so we're delighted to be partnering with Quantcast to help us deliver precision targeting of our progressive audience to advertisers."
Phil Macauley, managing director at Quantcast, said: "Leading brands are constantly striving to maximise the value of their advertising investment. Our technology makes it easy to reach their target audience within a premium publication, such as the Guardian, and therefore delivers that very value.
"At the same time it provides a better online experience for consumers, who see ads that are relevant to them."