Dialectica geometra is a moth of the Gracillariidae family. It is known from Hong Kong, Japan (the Ryukyu Islands), India (West Bengal, Tamil Nadu, Bihar, Delhi and Uttar Pradesh) and Réunion. It has recently been recorded from China. The wingspan is 6.5-8.2 mm. The larvae feed on Cordia amplifolia, Cordia myxa, Ehretia laevis and Ehretia species, including Ehretia microphylla. They mine the leaves of their host plant.