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Joseph (Jay) B. Darby III

Joseph (“Jay”) B. Darby III has more than thirty years of experience representing clients in a wide range of tax, estate planning, and related business matters. His goal is to help clients enjoy their lives by reducing taxes, avoiding (or resolving) problems with taxing authorities, and passing personal wealth to the appropriate next destination.  


Jay's clients range from individuals to large public and private business entities, and while he has structured some of the most sophisticated transactions in the business arena, he is mindful of the fact that people rather than businesses ultimately pay taxes. Therefore, he always structures transactions with the goal of minimizing the tax costs and maximizing the after-tax return for the people he represents.


An early proponent of Opportunity Zones (an investment incentive created under the 2017 Tax Act), Jay has become one of the country’s go-to experts in the area, helping clients bring business investment and ultimately prosperity to some of the most challenged areas of the country.

Jay is the author of a highly acclaimed treatise, Practical Guide to Mergers, Acquisitions and Business Sales (click here to purchase). He has written more than 1,000 articles on

tax, business, and a diverse range of other topics. He teaches numerous advanced tax courses at Boston University School of Law's Graduate Tax Program, and has taught regularly at Boston College Law School and Bentley College (in the Masters of Taxation program). He is a popular speaker on the national tax conference and webinar circuit, lecturing regularly on a wide range of topics. He is also the founder and principal host of the OZoom Forum, a video-conferencing platform sponsored by Boston University School of Law that provides a venue for sharing information and ideas about Opportunity Zones and related subjects.


Jay’s many awards and honors include being recognized in the area of tax practice by Best Lawyers in America®, being recognized for his achievements in Legal 500 U.S., being named a “Top 25 Opportunity Zone Influencer” by Opportunity Zone Expo Magazine, and receiving an AV Preeminent®, Martindale-Hubbell® Peer Review Rating™. 


Jay was a partner at some of the largest and most prestigious law firms in the country, including Greenberg Traurig LLP and Holland & Knight LLP, before founding his own firm, Joseph Darby Law PC.






J.D., 1978, Cum Laude, Harvard Law School

B.S., 1974, Magna Cum Laude, University of Illinois

(with Departmental Honors in Mathematics)

Bar & Court Admissions


U.S, Tax Court


Best Lawyers in America® (2010–2021)
Legal 500 U.S. (2014, 2015, 2019–2020)

AV Preeminent®, Martindale-Hubbell® Peer Review Ratings™ (the highest level of professional excellence, skill, and integrity)
Top 25 Opportunity Zone Influencer, OZ Magazine (2019 and 2020)
Tax Writer of the Year, World Trade Executive, a division of Thomson Reuters (2007 and 2011)
New England Press Association, First Place for Sports Column writing (1990)
Special Recognition Award, "Honorary Armenian," from the Armenian Library and Museum of America (1988) (for contributing hundreds of hours of legal work to help ALMA obtain tax-exempt financing to acquire a permanent museum facility, located in Watertown, MA)


Writer's Council, OZ Magazine (2019–Present)

University Appointments

  • Adjunct Professor, Boston University School of Law, Graduate Tax Program (2003–Present)

    • TX920​ Tax Aspects of Buying and Selling a Business

    • TX930 Partnership Taxation

    • TX944 Structuring Intellectual Property Transactions

    • TX955 Taxation of Intellectual Property

    • TX970 Opportunity Zones

    • TX988 Xtreme Estate Planning: Because Life is Like the X Games 

  • Adjunct Professor, Advanced Tax course, Boston College Law School (2015–2020)

    • Tax III Advanced Tax​

  • Adjunct Professor, Masters in Taxation Program, Bentley University (2007–2017)

    • Taxation of Intellectual Property​

    • Tax Aspects of Buying and Selling a Business

Speaking Engagements

​Member of the Advisory Board of World Trade Executive for the following publications:

  • Practical US/International Tax Strategies

  • Practical European Tax Strategies

  • Practical US/Domestic Tax Strategies

Boston Estate Planning Council


American Bar Association, Tax Section


Boston Bar Association

Member, Board of Assessors, Watertown, MA (1993–2011)

Founder and President, Watertown Police Foundation (2013–Present) (created to help Watertown recover from the violent events that led to the capture of the Boston Marathon bombers in April 2013) 

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