| Succession: | Maharana of Mewar |
| Reign: | 30 January 1528 – 1531 |
| Predecessor: | Rana Sanga |
| Successor: | Vikramaditya Singh |
| Dynasty: | Sisodias of Mewar |
| Death Date: | 1531 |
| Father: | Rana Sanga |
| Mother: | Rani Dhan Bai Rathore of Marwar |
Ratan Singh II[1] (died 1531) was the Maharana (r. 1528 – 1531) of Mewar Kingdom. He was a son of Rana Sanga.[2] He was killed during a war in 1531. He was succeeded by his surviving brother Vikramaditya Singh.[3]
His wives were Rani Guman Kanwar and Maharani Suja Bai of Bundi.[4]
Mahmud Khilji of Malwa was defeated by Sanga. He was waiting for an opportunity to fight with the ruler of Mewar. After the death of Sanga, he detached Shirza Khan with an army to lay waste the country of the Rana. According to Tarikh-i-Alfi, he was actuated by these three motives (i) to chastise Rana (ii) to recover some territories of Malwa, which had been captured by Sanga and (iii) to punish Silahadi Tanwar, who was in concert with Rana and had recently seized some territory belonging to the kingdom of Malwa. But the attempts of the Sultan proved futile as Shirza Khan was badly defeated. At the same time, Maharana with a large army penetrated into Malwa and reached village of Sambaliya (Near Sarangpur). Having ravaged the country around it, he then proceeded towards Ujjain to confront Sultan Mahmud Khilji II of Malwa. At the time when Maharana Sanga entered into Malwa, the Sultan of Gujrat, being in concert with the Sultan of Malwa, had extended necessary help to the latter. But soon, the situation changed. Dissensions had broken out between these Sultans. Due to his arrogant temper, Sultan Mahmud Khilji of Malwa could not develop his faith among his adherents. He then summoned Mohin Khan of Sewas and Silahady to help him against the invasion of Mewar. When they waited on him, they were given some extraordinary honours. Both of them, suspecting foul play, deserted him and went to the camp of Maharana which had disheartened the Sultan. The Mewar army succeeded in defeating the Malwa-troops neat Ujjain and carried out depredations successfully.[5]