Macroglossum tenebrosa is a moth of the family Sphingidae first described by Thomas Pennington Lucas in 1891.

It is known from Sulawesi, the Moluccas, Aru, Papua New Guinea, the Bismarck Archipelago, the Solomon Islands and north-eastern Australia.

The abdomen upperside tergites are glossy bluish grey when side lit, apart from some black patches.

The hindwing upperside is bluish white near the anal angle, with a bluish-white streak.

The larvae are white with brown stripes and have a yellow head and thorax.