Embodiments of the invention describe parasitic capacitance reduction structure for nanowire transistors and method of manufacturing. According to one embodiment the method includes providing a substrate, forming a first nanowire on the substrate, forming a second nanowire on the first nanowire, forming a first dielectric layer between the substrate and the first nanowire, and forming a second dielectric layer between first dielectric layer and the second nanowire, where the second dielectric layer has a higher dielectric constant than the first dielectric layer. According to one embodiment, a nanowire transistor includes a first nanowire on a substrate, a second nanowire on the second nanowire, a first dielectric layer between the substrate and the first nanowire, and a second dielectric layer between the first dielectric layer and the second nanowire, where the second dielectric layer has a higher dielectric constant than the first dielectric layer.