The types of intermolecular forces present in ammonia, or NH3, are hydrogen bonds. The hydrogen bonds are many magnitudes stronger than other intermolecular forces in NH3; therefore, when examining intermolecular bonding in this molecule, other forces can be safely ignored.
Hydrogen bonds are a strong type of dipole-dipole interaction that only happens between molecules that have a hydrogen atom covalently bonded to an oxygen, nitrogen or fluorine atom. Water, or H2O, has even stronger hydrogen bonds than NH3. Chemicals with hydrogen bonding exhibit far higher boiling points than chemicals of similar molecular weight whose main intermolecular force is not from hydrogen bonds.