The Western Satraps, or Western Kshatrapas (Brahmi:, Mahakṣatrapa, "Great Satraps") were Indo-Scythian (Saka) rulers of the western and central parts of India (extending from Saurashtra in the south and Malwa in the east, covering modern-day Sindh, Gujarat, Maharashtra, Rajasthan and Madhya Pradesh states), between 35 and 415 CE. The Western Satraps were contemporaneous with the Kushans who ruled the northern part of the Indian subcontinent, and were possibly vassals of the Kushans. They were also contemporaneous with the Satavahana (Andhra) who ruled in Central India. They are called "Western Satraps" in modern historiography in order to differentiate them from the "Northern Satraps", who ruled in Punjab and Mathura until the 2nd century CE.
The power of the Western Satraps started to decline in the 2nd century CE after the Saka rulers were defeated by the Emperor Gautamiputra Satakarni of the Satavahana dynasty. After this, the Saka kingdom revived, but was ultimately destroyed by Chandragupta II of the Gupta Empire in the 4th century CE. The Western Satraps, having been defeated by the Abhiras/Ahirs, declined rapidly during the second half of the third century.
Altogether, there were 27 independent Western Satrap rulers during a period of about 350 years.
They are named Western Satraps in contrast to the "Northern Satraps" who ruled around East Punjab and the area of Mathura, such as Rajuvula, and his successors under the Kushans, the "Great Satrap" Kharapallana and the "Satrap" Vanaspara.
Although they called themselves "Satraps" on their coins, leading to their modern designation of "Western Satraps", Ptolemy in his 2nd century "Geographia" still called them "Indo-Scythians". The word Kṣatrapa has the same origin as the word satrap and are both descended from Median xšaθrapāvan-, which means viceroy or governor of a province, and according to John Marshall, the word kṣatrapa means the viceroy of the "King of kings". The title of the Mahakṣatrapa or the "Great Satrap" was given to the ruling Satrap, and the title of kṣatrapa was given to the heir apparent.