The winning poster was designed by 14-year-old Natasha Truman from North London and will be distributed to schools and in Sugar this week.
Sugar and the NSPCC invited the magazine's 555,000 readers to design the poster to support the NSPCC's "Stand up speak out" campaign and Anti-Bullying Week from November 20-24. The poster includes the number for ChildLine, the support line run by the NSPCC.
The hundreds of entries were reduced to a shortlist of six by judges from the NSPCC, the magazine and the agency, and then Sugar readers voted via its website for the winner.
Chris Cloke, the NSPCC's head of child protection awareness and chair of the Anti-Bullying Alliance, said: "We hope Sugar's poster sends out a clear message that bullying is totally unacceptable and how important it is that we all speak out about it."
Annabel Brog, editor of the Hachette Filipacchi-owned magazine, said: "It's proof not only how committed teenagers are to preventing bullying, but also how proactive they can be, and how strongly they can respond when they are engaged and inspired to act."
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