LAWYER PROFILE

Ariane Guimarães

Brazil 2026

Mattos Filho

Ranked in 1 practice area

Tax: Brasília

Brazil

1 year ranked

About

Provided by Mattos Filho

Brazil: Regions

Practice Areas

Tax; Government Relations; Mattos Filho 100% Pro Bono

Career

Ariane focuses her practice on tax litigation, particularly on legal strategies in Brazil’s superior courts. She assists clients with managing the impacts of court decisions on business and represents interests before the executive (Ministry of Economy) and legislative branches (National Treasury Policy Council and National Congress), coordinating the firm’s Government Relations practice. A vice-chairman of the Brazilian Bar Association – Federal District Chapter’s Superior Courts Commission (2022-2024), Ariane is also vice-president of the Legislation Committee of the American Chamber of Commerce (Amcham).

Ariane is a professor of Tax Law at the Centro Universitário de Brasília (UniCEUB), the founder and coordinator of the Group of Studies and Research in Tax Law (Gepat), as well as the founder of ‘Elas Pedem Vista’, a group that discusses current issues related to women in power. She is also a member of the firm’s Pro Bono Committee.

Education

Centro Universitário de Brasília (UniCEUB)

Bachelor of Laws

Centro Universitário de Brasília (UniCEUB)

Master in Tax Law

Centro Universitário de Brasília (UniCEUB)

Doctorate in Tax Law

Georgetown University, USA

Visiting Researcher

Languages Spoken

Portuguese;

English;

Chambers Review

Provided by Chambers

Chambers Brazil: Regions

Tax: Brasília - Brazil

Band 1

Individual Editorial

Ariane Costa Guimarães is a highly regarded tax disputes practitioner with a strong track record before the higher courts. She is recognised for her role in complex and high-value litigation, including leading cases under the general repercussion system. Ariane regularly represents major companies and industry associations in matters with nationwide impact. Her work is particularly noted for its strategic approach and distinctive perspective on tax procedure and jurisprudence.

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Strengths

Provided by Chambers

A highly qualified professional with in‑depth knowledge, Ariane Guimarães is also exceptionally up to date and highly attuned to the client’s needs and limitations.
Tax: BrasíliaChambers Brazil: Regions
Ariane is an excellent lawyer: intelligent, helpful and highly skilled.
Tax: BrasíliaChambers Brazil: Regions
Ariane Guimarães is an exceptional and highly qualified lawyer, combining outstanding technical ability with a strong human approach. She is a source of inspiration, encouraging those around her to perform at their best.
Tax: BrasíliaChambers Brazil: Regions