The Leader of the Opposition is the parliamentary chairperson of the largest political party in their respective legislative chamber that is not in government.

While the position also existed in former Central Legislative Assembly of British India, and holders of it there included Motilal Nehru, it received statutory recognition through the Salary and Allowances of Leaders of Opposition in Parliament Act, 1977 which defines the term "Leader of the Opposition" as that member of the Lok Sabha or the Rajya Sabha who, for the time being, is the Leader of that House of the Party in Opposition to the Government having the greatest numerical strength and recognised, as such, by the Chairman of the Rajya Sabha or the Speaker of the Lok Sabha.

[1][2] As per the Salary and Allowances of Leaders of Opposition in Parliament Act, 1977 by which the post has got official and statutory status, the majority required is decided by the heads of the houses, that is speaker and chairman as the case may be.

[4] For this purpose direction 121(c) was issued which laid down the recognition of a party or group in Lok Sabha as having “at least a strength equal to the quorum fixed to constitute a sitting of the House, that is one-tenth of the total number of members of the House”.

This is not an official or constitutional post, however still exists to bring political stability and strength to the Opposition party in Government.