A novel model of a nonlocal magneto-thermoelastic porous solid in the context of the three-phase-lag model with a memory-dependent derivative is introduced. The effect of a magnetic field on a nonlocal thermoelastic porous medium in the context of a three-phase-lag model with memory-dependent derivatives was studied. The normal mode analysis is used to solve the problem of an isothermal boundary to obtain the exact expressions of physical fields. The numerical results are represented to estimate the effects of the magnetic field, time delay, and the nonlocal parameter on the behavior of all of the field variables such as temperature, displacement, and stresses. Comparisons are given for the results in the absence and presence of the magnetic field as well as the locality. Comparisons are also given for the results for different values of time delay. To the best of the author’s knowledge, this model is reported for the first time. Some particular cases are also deduced from the present investigation.