We present the results obtained by superconducting quantum interference device (SQUID) magnetometry, specific heat, and M¨ossbauer spectroscopy measurements carried out on Np2Ni17 polycrystalline samples. We show that long-range magnetic order, with a moment μ(2b) ∼ 2.25 μB, occurs below TN = 17.5 K on the Np (2b) sites. A nontrivial situation is observed in that the other Np sites (2d) do not take part to the order transition and carry only an induced moment of about 0.2 μB below TN. A combined analysis of the different experimental data sets allowed us to determine key parameters associated with the electronic structure of the system. The experimental results are discussed against first-principles electronic structure calculations based on the spin-polarized local spin density approximation plus Hubbard interaction. ; JRC.E.6-Actinide research