big brothers big sisters of the fox valley region is a volunteer organization that provides children support, guidance, friendship and fun by matching them to adult role models. for more than 40 years, big brothers big sisters has fulfilled their mission of enriching, encouraging and empowering children to reach their highest potential through safe, positive mentoring relationships.big brothers big sisters of the fox valley regin serves waupaca, outagamie, winnabago and calumet counties. we are a volunteer organization serving children and youth from appleton to oshkosh. formerly big brothers/big sisters.