''Elachista bidens'' is a moth of the family Elachistidae that is found in Western Australia. The wingspan is about for males and for females. The forewings are blue. The hindwings are grey. The larvae feed on ''Lepidosperma tuberculatum''. They mine the leaves of their host plant. The mine is straight, whitish and reaches a length of about . Pupation takes place outside of the mine on a leaf of the host plant.

References

Moths described in 2011 Endemic fauna of Australia bidens Moths of Australia Taxa named by Lauri Kaila {{Elachista-stub