This chapter is focused on the synthesis and properties of acrylic/clay nanocomposite pressure-sensitive adhesives (PSA), which are an example of use of low glass transition temperature acrylic/clay nanocomposite materials. These acrylic/clay nanocomposites can be synthesized in situ, by carrying out an emulsion or suspension (co)polymerization of a chosen monomer or monomers in the presence of clay. The properties of a PSA depend upon balance of three basic adhesive properties: tack, peel strength, and shear resistance. Hence, to be an effective PSA, the material needs a balance of elasticity and viscosity. Here it is shown how the incorporation of nanosized clay into PSA latex film offers an effective means to modify the viscoelastic properties of PSA, with the aim of optimizing the adhesive properties. The adhesive properties are changed according to the specific end use of the adhesive and can be adjusted by choosing an appropriate nanocomposite synthesis method and by using the proper type and amount of clay.