Transparency in Government Act of 2021 This bill establishes and otherwise modifies several reporting, disclosure, and other requirements across all branches of government to expand public access to information. For example, with respect to the legislative branch, the bill establishes additional financial disclosure requirements for Members of Congress, requires congressional committees to post certain materials (e.g., schedules and transcripts) within specified time frames, and provides for the creation of a centralized online database of congressionally mandated reports. Additionally, with respect to the executive branch, the bill requires agencies to publicly disclose additional information relating to sponsored advertisements, budget requests, and grant recipients; requires certain legal advisory opinions and rulemaking materials to be published within specified time frames; and provides for the appointment of a special counsel to prosecute individuals in the executive branch for contempt of Congress. Finally, with respect to the judicial branch, the bill requires the Supreme Court to allow proceedings that are conducted in open court to be televised, requires certain financial disclosure statements of judicial officers to be posted within specified time frames, and requires certain electronic filing systems to be consolidated and meet certain data standards (e.g., search functions).