Why is the dipole moment of acetone higher than ethanol? It is true that acetone is less polar than ethanol. 
I thought the dipole moment is proportional to polarity, and if so, the dipole moment of acetone should be lower than ethanol. 
But the dipole moment of acetone is higher than ethanol.
Why is it higher?
Dipole moment is just one of aspects of solvent polarity, as is well known in HPLC separation  analytical technique where the following effects take part:

Dipole moment interaction, permanent and induced
The above for the whole molecule and for particular bonds
Electron pair donor
Electron pair acceptor (including $\ce{H+}$ donation)    

Depending on solute molecules specifics, the solvent polarity order is variable, as various molecules have different responses to above interactions.

See also Using solvent triangle in HPLC