A flutter analysis, employing slender-body aerodynamic theory and thin-plate theory, is made for rectangular wings of very low aspect ratio with a constant thickness. The spanwise variation of wing deflection is assumed to be given by a parabola, and the chordwise variation is allowed complete freedom. The results show the vsriation of flutter speed and male shape with aspect ratio. Comparisons are made with additional resuits obtained by approximating the chordwise deflection shape by use of parabolic or cubic curves. The analysis shows that the cubic approximation gives good resuits for a ratio of chord to semispan less than 3.