Wars involving ancient India

Around 535 BCE, the Persian king Cyrus the Great initiated a protracted campaign to absorb parts of India into his nascent Achaemenid Empire. In this initial incursion, the Persian army annexed a large region to the west of the Indus River, consolidating the early eastern borders of their new realm. With a brief pause after Cyrus' death around 530 BCE, the campaign continued under Darius the Great, who began to re-conquer former provinces and further expand the Achaemenid Empire's political boundaries. Around 518 BCE, the Persian army pushed further into India to initiate a second period of conquest by annexing regions up to the Jhelum River in what is today known as Punjab. At peak, the Persians managed to take control of most of modern-day Pakistan and incorporate it into their territory.

The Shunga-Greek War comprised several conflicts between the Shunga Empire and the Greco-Bactrian Kingdom. It is predominantly based on the Sanskrit play "Mālavikāgnimitram".

The Saka—Satavahana wars were a series of conflicts between the Western Satraps and the Satavahanas in the first and second century CE. Both sides achieved success at varying points during the conflicts, but in the end, the Satavahanas prevailed. However, constant wars with the Sakas severely weakened them and was a major contributor in their fall.

The Battle of the Ten Kings (Sanskrit: दाशराज्ञ युद्ध, IAST: Dāśarājñá yuddhá) was first alluded to in the 7th Mandala of the Rigveda (RV) and took place between a king of the Bharatas named King Sudas versus a confederation of tribes. It resulted in a decisive victory for the Bharatas and subsequent formation of the Kuru polity. The Battle of the Ten Kings, mentioned in the Rigveda may have "formed the 'nucleus' of story" of the Kurukshetra War in the Mahabharata.

The Kalinga war (ended c.) was fought in ancient India between the Mauryan Empire under Ashoka the Great and Kalinga, an independent feudal kingdom located on the east coast, in the present-day state of Odisha and northern parts of Andhra Pradesh. It is presumed that the battle was fought on Dhauli hills in Dhauli which is situated on the banks of Daya River. The Kalinga War was one of the largest and deadliest battles in Indian history.

The Battle of the Hydaspes also known as Battle of Jhelum, or First Battle of Jhelum, was fought between Alexander the Great and Porus in May of 326 BCE. It took place on the banks of the Hydaspes River in what is now the Punjab province of Pakistan, as part of Alexander's Indian campaign. In what was possibly their most costly engagement, the Macedonian army secured a decisive victory over the Pauravas and captured Porus. Large areas of Punjab were subsequently absorbed into the Macedonian Empire; Porus was reinstated as the region's ruler after Alexander, having developed a newfound respect for the fierce resistance put up by Porus and his army, appointed him as a satrap.

The Gupta–Saka Wars refers to the military conflict between the Gupta Empire and the Western Satraps during the 4th century CE. Chandragupta II, also known as Chandragupta Vikramaditya, was a prominent ruler of the Gupta Empire during the 4th century CE. His reign is marked by significant military achievements, notably his subjugation of the Western Satraps who ruled in west-central India. Chandragupta II's success against the Western Satraps is attested by a combination of historical and literary evidence.

The Gauda–Gupta War was a conflict between Gopachandra on one side with Ishanavarman and Jivitagupta I on the other side. The war resulted in the defeat of the Gauda Kingdom.

The Avanti-Magadhan war was fought between Magadha and Avanti for domination over much of North India.

The Magadha–Vajji war was a conflict between the Haryanka dynasty of Magadha and the neighbouring Vajjika League which was led by the Licchavikas. The conflict is remembered in both Buddhist and Jain traditions. The conflict ended in defeat for the Vajjika League, and the Māgadhīs annexing their territory.