Regulatory Flexibility Improvements Act of 2011 - Amends the Regulatory Flexibility Act of 1980 (RFA) to: (1) define the "economic impact" of a proposed or final rule to include both direct economic effects on small entities and any indirect economic effects which are reasonably foreseeable and result from such proposed or final rule, and (2) include tribal organizations within the definition of "small governmental jurisdictions" for purposes of such Act. Requires initial and final regulatory flexibility analyses under RFA to: (1) describe alternatives to a proposed rule that minimize any adverse significant economic impact or maximize the beneficial significant economic impact on small entities, and (2) include revisions or amendments to a land management plan developed by the Secretary of Agriculture or the Secretary of the Interior under specified Acts. Requires the Internal Revenue Service (IRS) to comply with RFA requirements when codifying a regulation in the Code of Federal Regulations that imposes a collection-of-information or recordkeeping requirement. Revises the definition of "small organization" under RFA to include consideration of size standards, net worth, and the number of employees. (Sec. 3) Requires each federal agency to include in its regulatory flexibility agenda a description of the sector of the North American Industrial Classification System that is affected by a proposed agency rule which is likely to have a significant economic impact on a substantial number of small entities. (Sec. 4) Requires an agency to include in its initial regulatory flexibility analysis a detailed statement, including: (1) a description of why action by the agency is being considered and the objectives of, and legal basis for, the proposed rule; (2) an estimate of the number and types of small entities to which the proposed rule will apply; (3) the projected compliance requirements of the proposed rule; (4) an estimate of the additional cumulative economic impact of the proposed rule, or of any other rule stemming from the implementation of the Free Trade Agreements, on small entities; and (5) a description of any disproportionate economic impact on small entities or a specific class of such entities. Requires an agency, in developing an initial and final regulatory flexibility analysis, to provide a quantifiable or numerical description of the effects of a proposed or final rule and alternatives to such rule, or a more general descriptive statement and a detailed statement explaining why quantification is not practicable or reliable. (Sec. 5) Repeals agency authority to waive an initial regulatory flexibility analysis or delay a final regulatory flexibility analysis in emergency situations. Authorizes the Chief Counsel for Advocacy of the Small Business Administration (SBA) to make rules governing agency compliance with RFA requirements and to intervene in agency adjudications. (Sec. 6) Revises requirements for agency notification of the Chief Counsel prior to the publication of any proposed rule that is likely to result in: (1) an annual effect of the economy of $100 million or more; (2) a major increase in costs or prices; (3) a significant adverse effect on competition, employment, investment, productivity, innovation, or the ability of U.S. enterprises to compete internationally; or (4) a significant economic impact on a substantial number of small entities. Requires agencies to provide the Chief Counsel with: (1) all materials prepared or utilized in making the proposed rule, and (2) information on the potential adverse and beneficial economic impacts of the proposed rule on small entities. Requires the Chief Counsel to convene a panel to review such materials. Authorizes the Chief Counsel to waive such review requirements upon determining that compliance with such requirements is impracticable, unnecessary, or contrary to the public interest. (Sec. 7) Expands requirements for the periodic review of agency rules to require an agency to: (1) publish its plan for periodic review of agency rules determined to have a significant economic impact on small entities on its website; (2) detail in its plan how it will conduct outreach to include small businesses in the review process; (3) submit an annual report on the results of its review to Congress, the Chief Counsel , and the Administrator of the Office of Information and Regulatory Affairs of the Office of Management and Budget (OMB); (4) amend or rescind a rule to minimize any adverse economic impact on small entities or to maximize any beneficial impact on such entities, taking into account specified factors; and (5) publish in the Federal Register and on its website a list of rules to be reviewed under its plan. (Sec. 8) Allows judicial review of agency compliance with requirements of RFA when an agency publishes a final rule (currently, when final agency action is completed). Authorizes the Chief Counsel to file an amicus curiae brief in cases concerning agency compliance with RFA. (Sec. 9) Amends the federal judicial code to grant exclusive jurisdiction to the U.S. Courts of Appeals to review all final rules promulgated by the Chief Counsel governing agency compliance with RFA. (Sec. 11) Amends the Small Business Regulatory Enforcement Fairness Act of 1996 to require federal agencies, in preparing small entity compliance guides, to solicit input from affected small entities or associations of small entities.