Low velocity impact response of micro-cantilever beams made of axially functionally graded materials (AFG) is analytically investigated in present research based on the modified couple stress theory. Taking into account the temperature-dependency, material properties of polymer beam reinforced by carbon nanotubes are estimated using refined rule of mixture. The results are validated with those available in the literature. Finally, the temperature-dependent analysis are carried out to study the influences of material length scale parameter, CNTs distribution, CNTs volume fraction, impact position, impactor initial velocity and impactor radius on the low velocity impact behavior of AFG CNT reinforced micro-cantilever beams.