We present a fit to determine parton distribution functions (PDFs) using inclusive W± and Z/γ∗ boson and top-antitop production measurements from ATLAS in combination with deep-inelastic scattering data from HERA. The ATLAS W and Z boson data exhibit sensitivity to the valence quark distributions and the light quark sea composition, whereas the top-quark pair production data have sensitivity to the gluon distribution. The impact of the top-antitop production data is increased by fitting several distributions simultaneously. To achieve this, full information on the systematic and statistical correlations between data points in different spectra is required. The information on statistical correlations, both between bins and between the different top spectra are made available, and the impact of the top-quark pair production data using these correlations is assessed.