It is endemic to the Philippine island of Panay, particularly the mountains of Antique and Iloilo provinces.

One of the most distinctive features of Rafflesia lobata is that some populations have flowers with a lobed diaphragm that opens outward.

It remains to be seen whether flower merousity has phylogenetic significance that should be taxonomically recognized.

Some populations of R. manillana, such as one at Bolos Point, Cagayan Valley, Luzon, also have flowers with lobed, outwardly curving diaphragms.

[2] The first population of R. lobata was discovered by the local conservation group studying Philippine Spotted Deer (Cervus alfredi).