Angle strain refers to the distortion of bond angles in a molecule compared to the ideal angles predicted by VSEPR theory. This strain occurs when atoms are forced into geometries that deviate from their preferred arrangements, often due to steric hindrance or ring strain in cyclic compounds. In organic chemistry, angle strain is commonly observed in small rings, such as cyclopropane and cyclobutane, where the bond angles are significantly less than the ideal tetrahedral angle of 109.5 degrees. This strain can lead to increased reactivity and instability in these molecules, influencing their chemical behavior.