Density functional theory (DFT) electronic structure calculations were carried out to predict the structures, energetics, and triplet-triplet (T-T) spectra for the low-lying tripler states of free-base porphin (PH2) and its beta-octahalogenated derivatives (beta-PH2X8; X = F, Cl, Br). The lowest tripler excited state of PH2 and beta-PH2X8 was found to retain D-2h symmetry with stretched C-beta-C-beta and C-beta-C-m bond distances. For free-base porphin, the singlet-tripler (S-0-T-1) gap obtained with the B3LYP functional was in excellent agreement with the experimental phosphorescence value. Excitation energies computed by time-dependent DFT also provided a fine account of the observed T-T spectrum. beta-Halogenation had little effect on the singlet-tripler gaps of porphin. The S-0-T-1 and S-0-T-2 splittings for beta-PH2X8 were within 0.1 eV of the corresponding splittings in the unsubstituted porphin. All bands in the T-T spectra of beta-PH2X8 were predicted to be significantly (up to 0.65 eV) red-shifted in comparison to corresponding bands of the unsubstituted porphin.