We describe a non-destructive and accurate fibre refractive index profiling method with high spatial resolution based on Quantitative Phase Microscopy. This technique entails taking a series of three bright-field images of an axisymmetric optical fibre with a conventional microscope, consisting of an in-focus image, and a pair of slightly defocused images. Using an algorithm based on the transport of intensity equation we can then calculate the phase across the fibre. Once the phase is known, it is then analysed using the inverse Abel transform. The refractive index profiles recovered using this method are shown to agree well with a commercial profiling instrument.