Computational n-octanol/water partition coefficients data for 75 chloronaphthalene congeners based on the Ghose, Pritchet, and Crippen algorithm; the Moriguchi method; and two QSPR models with principal component regression and partial least-squares (PLS) regression calculations are presented. Chloronaphthalenes log Kow data obtained after PLS are characterized by the lowest root mean square error (RMSEP = 0.0190), whereas results from the Ghose, Pritchet, and Crippen algorithm are characterized by the worst predictive ability (RMSEP = 0.4191). Minimal values of log Kow of chloronaphthalenes ranged between 3.57 and 3.90 for 1-chloronaphthalene, whereas maximal values ranged between 6.36 and 7.19 for octachloronaphthalene.