Jashodaben Modi, 62, a retired primary school teacher, has been thrown into the national spotlight since Modi, after years of silence, disclosed his marriage in an election filing last month.
She has gone on pilgrimages in the Himalayas twice in recent weeks to avoid reporters swarming to her windowless rooms in the cramped house she shares with her brother's family in Gujarat state.
After Modi, 63, is sworn in as 15th prime minister of the world's biggest democracy on Monday, men of the Special Protection Group (SPG) - an elite force modelled on the Secret Service that guards U.S. presidents - will take over his security.
Under law, the SPG is responsible for the security of the prime minister and his immediate family members.
"The SPG has made general inquiries regarding Jashodaben. The lead agency will be the state police and the SPG will have to depend on them," a source in the Gujarat police told Reuters.
Another security official in New Delhi said Jashodaben and Modi's 95-year-old mother were entitled to top-level cover and that neither could refuse, although the protection could vary according to the perception of threat.
Modi is one of India's most guarded politicians. Earlier this year there were warnings that members of the Indian Mujahideen were plotting to target him at an election rally.
A LIFE IN THE SHADOWS
Jashodaben's family said they were not aware of any plans to mount security for her. "She lives a life immersed in prayers, she doesn't need any of this," said her brother, Ashok Modi, who runs a small provision shop from the front portion of his house.
"What she would like is to get back to her husband as every woman in our society wants. But that won't happen," he said. Modi is a common name in Gujarat.
Another brother, Kamlesh, who lives a few houses away and sells onions to supplement his income, said their village of 2,500 was pleased Modi had finally owned up to the marriage.
"There is hope here that something good will come to this village, now that he is prime minister," Kamlesh said, sitting in a sweltering mud-walled house.
Prime Minister Modi has never spoken about his wife, but friends and family say the couple were married off while they were still in their teens after their parents had spoken for them, in the tradition of the time, especially in poor families.
But Modi left home soon after, drawn into the ascetic life of the Hindu nationalist volunteer group Rashtriya Swayamsevak Sangh (RSS), many of whose top leaders practised celibacy to focus on the organisation's cause of nation-building.
In a rare interview to a Gujarati television channel broadcast last week, Jashodaben said that after the wedding, Modi was busy working for the RSS across the country and suggested she return home.
"When I came to Vadnagar to live with his family, he told me 'why did you come to your in-laws' house when you are still so young You must instead focus on pursuing your studies'," she said. "The decision to leave was my own and there was never any conflict between us."
Modi moved away from his family as he plunged into politics and, unlike many other politicians whose sons and daughters have inherited power and fame, he has kept a distance from them.
During each of the three elections he fought in Gujarat, where he served as chief minister, Modi left blank the question of his marital status on the candidate form. But in April, fearing rivals could try to get him disqualified, he sought to clear the air.