The campaign, devised by Wax Communications, aims to raise money for WWF's Antarctica and Southern Oceans Programme, which creates marine protected areas for sea life in the region.
United Biscuit's Penguin wrappers feature details about the project, and offer consumers who send in the special wrapper along with £5.99, or £6.99 without the packaging, a soft penguin toy, Antarctic wall chart and information on how to get more involved with the WWF campaign work.
The on-pack work also flags an Inbox Digital-created website called , containing details about the Antarctic penguin colony.
McVitie's Penguin said the key objective of the campaign was to reposition the brand as more responsible and drive engagement for conservation, climate change and the WWF's work.
Sophie Boston, Wax Communications' senior account manager, said: "The idea of sponsoring a penguin gives consumers a way to engage with the issue and to take action that will truly help.
"We wanted to communicate with kids and parents, and a cuddly penguin backed up with clear information about the penguin's plight and ways to help further will stimulate interest in this worthy cause."