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A significant fraction of exoplanetary systems is known to exhibit spin-orbit misalignments. This surprising fact has been mainly revealed by a spectroscopic method, known as the Rossiter-McLaughlin effect for transiting planetary systems. This method measures the projected angle between the stellar spin and the planetary orbital axes, but is insensitive to the obliquity of the stellar spin with respect to the observer. Asteroseismology offers a unique method to infer the stellar obliquity in a complementary fashion. In this talk, I will first review the current statistics of the observed spin-orbit angles and proposed models for the origin of the misalignment. Then I will show our recent work on the spin-orbit architecture of transiting planetary systems using asteroseismology, and discuss its implications.