In this talk I will review three possible ways to measure weak lensing using supernova Ia observations.

In detail, I will start focusing on the lensing signal detection on the Hubble Diagram (and the future use as cosmological probe), then I will describe the correlations between the supernova magnitude and the reconstructed density field along the line-of-sight. Finally, I will show predictions of the magnitude-magnitude correlation function for DES and LSST.