We present results of an investigation of the static magnetic susceptibility of Zn1-xMnxSe for x=0.05, 0.15, 0.30, and 0.45. From the Curie-Weiss behavior of the susceptibility at high temperatures, we determine the effective Mn-Mn exchange constant J1 to be -13.5±0.95 K. By using the results of our study in conjunction with direct measurements of the nearest-neighbor exchange integral JNN from inelastic neutron scattering by nearest-neighbor pairs, we obtain an estimate of the next-nearest-neighbor exchange constant J2=-2.4 K.