Adhesives suitable for use with low surface energy materials are described. The adhesive contain an acrylic copolymer, a high glass transition temperature tackifier and a low glass transition temperature tackifier. The acrylic copolymer is the reaction product of a first alkyl(meth)acrylate having at least 5 carbon atoms in the alkyl group, a second alkyl(meth)acrylate having 1 to 4 carbon atoms in the alkyl group, and a vinyl carboxylic acid. Both tackifiers have a Tg greater than the Tg of the acrylic copolymer. The high glass transition temperature tackifier has a Tg of at least 20° C. and the low glass transition temperature tackifier has a Tg of less than 0° C.