Carbon tetrachloride is a non-polar molecule. Although there are dipoles present in the molecule, due to the difference in electronegativities between carbon and chloride atoms, the linear shape of the molecule means that the molecule as a whole is non-polar.
Polar molecules must have at least one dipole present, but can have more as well. A molecule with dipoles may or may not be polar, depending on its geometry. A symmetrical molecule is non-polar, but a non-symmetrical molecule with dipoles is polar. One example of a polar molecule is water, due to the hydrogen atoms attaching to oxygen at different angles.