Jennifer Koo, Esq.


About Jennifer

Jennifer Koo is a Partner with Sales Tax Defense LLC. The firm specializes in sales, use, and transaction taxes. Jennifer has been with the firm for over 14 years. Jennifer previously worked at the New York State Attorney General’s Office and brings her experience to her current position.

Areas of Practice

  • Multi-state sales and use tax consulting
  • Sales and use tax audit defense
  • Representation before government revenue agencies and auditors
  • Sales and use tax refunds and recovery
  • Sales tax planning and research
  • Due diligence reviews
  • Representing clients at Bureau of Conciliation and Mediation Services hearings
  • Workers’ compensation assistance
  • Representing clients at Administrative Law Judge hearings

Admitted to Practice Law in:

  • New York
  • Connecticut
  • Federal Court for the Eastern District of New York
  • United States Tax Court
  • United States Supreme Court

Additional Experience

  • Mediator and Arbitrator with Nassau County Small Claims Court 2023-present

Professional Affiliations:

  • Asian Advisory Council to the Nassau District Attorney, Member
  • New York State Bar Association, Member
  • Nassau County Bar Association, Member
    • Member of the Board of Directors 2017-2020 and 2023-present
    • Alternate Delegate to the New York State Bar Association’s House of Delegates 2023-present
    • Member of the Nassau Academy of Law Advisory Board 2020-present
    • Chair and Founding Member of the Asian American Attorney Section 2023-present
    • Chair of the Association Membership Committee 2022-present
    • Co-Chair of the Business Law, Tax, and Accounting Committee 2019- 2022
    • Co-Chair of the Attorney Accountant Committee 2017-2019
    • Vice Chair of the Women in Law Committee 2017-2019
    • Co-Chair of the New Lawyers Committee 2015-2017
  • Suffolk County Bar Association, Member


  • Nassau Lawyer, Vol. 73, No. 3 November 2023
    “An Evening Discussing This Light Between Us and Asian Racism with Andrew Fukuda”
  • Nassau Lawyer, Vol. 71 No. 11, July/August 2022
    “A Review of the Killing of Vincent Chin: A Re-Enactment”
  • Nassau Lawyer, Vol. 68 No. 1, September 2018
    “Down with Quill – The New Precedent in Internet Sales Tax”
  • Nassau Lawyer, Vol. 59 No. 7, March 2010
    “What to do when you owe New York State Sales and Use Tax”
  • The National Conference of CPA Practitioners Nassau/Suffolk Chapter, Vol. 9 Issue 1, January 2012
    “Now that the Holidays are Over, it’s Time to Pay your Bills”
  • New York State Society of Certified Public Accountants Nassau Chapter, Vol. 57 No. 1, January 2013
    “How to Dispute a Sales Tax Assessment”


  • Long Island Business News,Leadership in Law honoree, 2023
  • Schneps Media, Power Women of Long Island honoree, 2023
  • Long Island Business News, Top 50 Women in Business honoree, 2022
  • Long Island Business News, Leadership in Law honoree, 2021


  • Juris Doctor – Hofstra University School of Law 2009
  • Bachelor of Science Cum Laude in Management and International Business – Ithaca College 2006

Interesting Facts About Jennifer

Jennifer was born and raised in Ohio, it is where she became a lover of the outdoors. In her spare time Jenn loves to go rock climbing as well as take her dog (a Shiba Inu mix) on long runs. Jenn is a brown belt in Shotokan Karate.

These days she spends much of her free time with her husband Kevin and her two children Madelyn and Hadrian.