Filed Pursuant to Rule 424(b)(7)

Registration No. 333-259706

Supplement No. 1

(To Prospectus dated October 5, 2021)

ReNew Energy Global Plc

PRIMARY OFFERING OF

20,226,773 CLASS A ORDINARY SHARES

SECONDARY OFFERING OF

271,479,759 CLASS A ORDINARY SHARES,

118,363,766 CLASS C ORDINARY SHARES,

7,026,807 WARRANTS TO PURCHASE CLASS A ORDINARY SHARES, AND

7,671,581 CLASS A ORDINARY SHARES UNDERLYING WARRANTS

This prospectus supplement updates and amends certain information contained in the prospectus dated October 5, 2021, or the “Prospectus”, covering the issuance from time to time by ReNew Energy Global plc, a public limited company organized under the laws of England  & Wales, or “we”, “our”, the “Company”, of up to 20,226,773 Class A Ordinary Shares, nominal value of $0.0001, or the “Class A Ordinary Shares,” including 7,026,807 Class  A Ordinary Shares issuable upon the exercise of Warrants that are held by RMG Sponsor II, LLC, or “RMG Sponsor II”, or “Private Warrants” and 11,499,966 Class  A Ordinary Shares issuable upon the exercise of Warrants held by the public warrant holders, or “Public Warrants”. The Prospectus also relates to the resale, from time to time, by the selling securityholders named therein, or the “Selling Securityholders”, or their pledgees, donees, transferees, or other successors in interest, of (a) up to 271,479,759 Class A Ordinary Shares, (b) up to 7,026,807 Private Warrants; (c)  up to 118,363,766 class C ordinary shares having a nominal value of $0.0001 per share, or “Class C Ordinary Shares”, and (d) up to 7,671,581 Class  A Ordinary Shares issuable upon exercises of the Private Warrants. You should read this supplement no. 1 in conjunction with the Prospectus. This prospectus supplement is not complete without, and may not be utilized except in connection with, the Prospectus, including any amendments or supplements thereto.

Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 7 of the Prospectus and other risk factors contained in the documents incorporated by reference therein for a discussion of information that should be considered in connection with an investment in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is October 5, 2021

The following information, presented as of October 5, 2021 is being provided to update the selling securityholders table in the Prospectus. Where the name of a Selling Securityholder identified in the table below also appears in the table in the Prospectus, the information set forth in the table below regarding that Selling Securityholder supersedes and replaces the information regarding such Selling Securityholder in the Prospectus. The percentages in the following table are based on 282,411,094 Class A Ordinary Shares outstanding as of September 20, 2021.

SELLING SECURITYHOLDERS