Leptogium subazureum is a species of corticolous (bark-dwelling) and foliose lichen in the family Collemataceae.

Found in India, it was formally described as a new species in 2010 by Archana Dube and Urmila Vasudev Makhija.

The type specimen was collected along the road from Ajra to Amboli (Maharashtra) at an elevation of 900 m (3,000 ft).

It grows along with mosses on the twigs and trunks of trees.

The specific epithet subazureum alludes to its resemblance with Leptogium azureum, which differs in ascospore size.