Yes, according to reports, Ranbir Kapoor has undergone hair transplant surgery.
While details are scarce and often rely on speculation and observation of his changing hairline over time, the provided reference explicitly states that Ranbir Kapoor, son of Rishi Kapoor, "has also undergone a hair transplant surgery."
It's worth noting that cosmetic procedures are often private, and public confirmations directly from the individuals involved are rare. Therefore, information is often based on observation and industry reports.