Mycale grandis, the orange keyhole sponge, is a species of marine demosponge in the family Mycalidae.

Water is drawn in through the oscula and expelled through the ostia after having had minute food particles removed by specialised cells.

[2][3] The native range of Mycale grandis is Australia, Indonesia, Malaysia and India.

It is part of the fouling community and is found on man made structures such as harbour walls, wharves and pilings and in disturbed habitats such as freshly dredged channels and lagoons.

Since then it has moved out of its normal habitats and is also found on reef slopes in Kāne'ohe Bay where it is overgrowing and suppressing native coral species such as Montipora capitata and Porites compressa.