Bangladesh, Bhutan (B), Brunei Darussalam, Cambodia, China (mainland), India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines (B), Singapore (B), Thailand, Vietnam.
Vagrant to Japan.
India to South East China and Indonesia. Accidental to Korea and Japan.
 
Population
Estimated population is unknown (2010).
Square-tailed Drongo-Cuckoo (Surniculus lugubris) [XC814571]
by Geoff Carey from Sarinbuana, Selemadeg, Tabanan Regency, Bali, Indonesia (song)
Square-tailed Drongo-Cuckoo (Surniculus lugubris) [XC648136]
by Bram Piot from Clement Town, Dehradun, Uttarakhand, India (song)
Subspecies
Forms a superspecies with Philippine Drongo-cuckoo (Surniculus velutinus), with which commonly considered conspecific, but song and juvenile plumage are distinct.
The following 5 subspecies are recognised:
dicruroides (Hodgson, 1839) - Punjab and lower Himalayas east through Nepal to Assam and Manipur, and from south-central China (Sichuan, Yunnan, Fujian, Hainan) south through Myanmar and Thailand to Indochina. Winters south to Malaysia, Sumatra (and Nias) and Java. Considered by some authors to be a distinct species, Fork-tailed Drongo-cuckoo (Surniculus dicruroides).
lugubris (Horsfield, 1821) - South-western coast of India (south of Goa), Sri Lanka, Java and Bali.
brachyurus Stresemann, 1913 - Malaysia, Sumatra and Bangka, Borneo and south-western Philippines (Palawan, Balabac, Calauit).
musschenbroeki A. B. Meyer, 1878 - Sulawesi and Butung to Bacan and Halmahera (northern Moluccas). Considered by some authors to be a distinct species, Moluccan Drongo-cuckoo (Surniculus musschenbroeki).
barussarum Oberholser, 1912 - Breeds north-eastern India, northern Myanmar, northern Thailand, northern Indochina, and south-eastern China, including Hainan. Winters south to Sumatra.