The present invention provides a chemical-mechanical polishing (CMP) composition suitable for polishing low-k dielectric materials. The composition comprises a particulate abrasive material, at least one silicone-free nonionic surfactant comprising a hydrophilic portion and a lipophilic portion, at least one silicone-containing nonionic surfactant comprising a hydrophilic portion and a lipophilic portion, and an aqueous carrier therefor. A CMP method for polishing a low-k dielectric surface utilizing the composition is also disclosed.