Infrared vibrational predissociation spectra are recorded for Br--(NH3)(n) (n = 1-4) and I--NH3 clusters in the N-H stretch region (3040-3460 cm(-1)). To aid spectral assignments and clarify structures of the Br--(NH3) clusters, ab initio calculations are performed at the MP2/aug-cc-pVDZ and MP2/aug-cc-pVTZ levels of theory, The Br--NH3 and I--NH3 dimers are predicted to have structures in which the NH3 molecule is attached to the halide anion by a single hydrogen-bond. The dominant infrared band for Br--NH3 at 3171 cm(-1) corresponds to a hydrogen-bonded N-H stretch vibrational mode, whereas two weaker bands are assigned to a symmetric stretch vibration of the nonboncled N-H groups (3347 cm(-1)) and to an ammonia-based bending overtone (3293 cm(-1)) deriving infrared intensity through Fermi interaction with the H-bonded N-H stretch mode. The corresponding I--NH3 spectrum is dominated by the H-bonded N-H stretch band at 3217 cm(-1), with three weaker bands at 3240, 3305, and 3360 cm(-1) assigned to two bending overtone vibrations and the nonbonded N-H symmetric stretch vibration, respectively. Spectra of the Br--(NH3)(n), n = 2-4, clusters are similar to the I--NH3 spectrum, exhibiting evidence for strong Fermi interactions between the H-bonded N-H stretch vibrational mode and ammonia-based bending overtones. On the basis of the infrared spectra and ab initio calculations, the larger Br--(NH3)(n) clusters are deduced to have structures in which the NH3 molecules are attached to the Br- by single H-bonds, but not necessarily to one other.