The NH3 molecule is trigonal pyramidal. It is asymmetrical so the bond dipoles do not cancel out and the molecule is therefore polar overall.

Is a pyramidal shape polar?

… The ammonia molecule has a trigonal pyramidal shape with the three hydrogen atoms and an unshared pair of electrons attached to the nitrogen atom. It is a polar molecule and is highly associated because of strong intermolecular hydrogen bonding.

Are trigonal molecules polar?

McCord - Trigonal Planar - 3 regions. If there are no lone pairs then the molecular geometry matches the electronic and is trigonal planar. ... POLARITY: NON-POLAR - As long as all three positions are the same, then the molecule cannot be polar due to perfect symmetry.