Shear wave splitting measurements across the North Anatolian Fault (NAF) in Northern Turkey are calculated from teleseismic SKS arrivals recorded by the dense temporary DANA seismological array to investigate the lithospheric anisotropy of an active shear zone. Our results show fast polarisation direction (φ) changes from NNE-SSW to NE-SW from south to north and a peak in splitting magnitude (δt) immediately north of the northern branch of the NAF. We show the first evidence for varying lithosphere-scale anisotropy across the NAF and suggest the presence of a strongly anisotropic region in the lower crust and/or upper mantle adjacent to the surface expression of the northern branch of the NAF (NNAF). We interpret multiple sources of anisotropy contributing to the overall splitting patterns, most likely dominated by distributed strain in the lithospheric mantle that is localised north of the NNAF.