We present the detailed optical evolution of a Type Ib SN 2015dj in NGC 7371, using data spanning up to ∼170 days after discovery. SN 2015dj shares similarity in light-curve shape with SN 2007gr and peaks at MV = ？17.37 ± 0.02 mag. Analytical modeling of the quasi bolometric light curve yields 0.06 ± 0.01 Me of 56Ni, ejecta mass Mej = 1.4 +1.3 -0.5 Me, and kinetic energy Ek = 0.7+ 0.6 - 0.3 10 51 erg. The spectral features show a fast evolution and resemble those of spherically symmetric ejecta. The analysis of nebular phase spectral lines indicates a progenitor mass between 13？20 Me, suggesting a binary scenario.