Dorset brewer Hall & Woodhouse is spending £6,000 sponsoring a campaign to stop adults buying alcohol for children in shops.
The Blitz Wize campaign will see posters going up in every off-licence in Dorset telling people that "proxy purchases" are illegal.
The posters will also be displayed in bus shelters as part of the wider police and council-backed Project Blitz campaign to tackle alcohol-related anti-social behaviour.
Mark Woodhouse, vice chairman of Hall & Woodhouse, said: "Producers and retailers of alcohol cannot ignore the issues that currently surround them. The vast majority of alcohol is consumed legally and responsibly, but we are very keen to play our part in the reduction of alcohol related anti-social behaviour.
"Project Blitz is a great initiative that has made a visible difference in Dorset, and we are delighted to be able to help highlight a key social problem that our pubs often get left to deal with."
Sgt Nikki Billington of Dorset Police said: "It wasn't so long ago that young people could quite easily buy alcohol themselves, but things have changed somewhat over the last few years.
"With the introduction of proof of age cards and frequent test-purchasing operations, buying alcohol underage is no longer so easy. Consequently, young people are now more inclined to ask older friends or relatives to buy it for them. This phase of Blitz is all about making people aware that it's illegal to buy alcohol for minors - and that anyone who does could receive a substantial fine."