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Maureen L. O'Leary-Guth is the President and owner of O'Leary-Guth Law Office, S.C. (previously, Willms-O'Leary, S.C.).  The firm was founded in 1990.  

  • Attorney O'Leary joined the firm in 2008 (then known as Willms, S.C., located in Thiensville, WI). 
  • Maureen acquired full ownership of the law firm in 2019.
  • Maureen was elected as a Fellow of the American College of Trust and Estate Counsel in 2021. 
  • In 2022 the firm acquired a larger Mequon office building to consolidate the firm's offices and allow room for further growth. 
  • In 2022 the firm was named Business of the Year by the Mequon-Thiensville Chamber of Commerce.
  • In 2023 the firm was named Small Business of the Year by Ozaukee Economic Development. 
  • In 2023 Maureen was named Professional Advisor of the Year by the Greater Milwaukee Foundation.
  • In 2024 Maureen was named to the Wisconsin Law Journal's PowerList of Estate Planning Attorneys and was named a Leader in Law by BizTimes Milwaukee.
  • In 2024 the firm was named a Best Places to Work winner by the Milwaukee Business Journal.

Maureen is the firm's managing attorney and oversees all of the firm's practice areas. Maureen focuses on high net worth estate planning, complex tax planning and business succession planning. Maureen also acts as an expert witness in trust litigation. 

Maureen is proud to be a Fellow of the American College of Trust and Estate Counsel ("ACTEC"), an esteemed group of many of the best trust and estate attorneys in the world.  Maureen is a member of ACTEC's Fiduciary Administration Committee and she is on ACTEC's Wisconsin Membership Committee.

Maureen is Past President of the Milwaukee Estate Planning Forum, a multi-disciplinary organization of estate planning professionals in the Greater Milwaukee area, focused on establishing and monitoring the highest professional and educational standards in the trusts and estates field.  

Maureen is also Past President of the Thiensville-Mequon Rotary Club and serves on numerous other boards.  

Maureen received her Juris Doctor degree with honors from Marquette University Law School and her undergraduate degree from Carroll College (now Carroll University).  Prior to law school, Maureen began her career in the business world as a shareholder and Operations Manager of a local company that she helped become a national franchise.  

Maureen lives in Glendale with her husband Attorney Jeremy Guth, their daughters, and their schnoodle.  

Publications Authored by Attorney O'Leary:

"Coming Soon: More Business Filing Requirements"

State Bar of Wisconsin Business Law Blog
June 21, 2022

"Business B Corps Certification: Displaying a High Standard"
State Bar of Wisconsin Business Law Blog
December 13, 2021

"Is Now the Time to Sell or Gift your Business?"
State Bar of Wisconsin Business Law Blog, August 25, 2021
Republished by InsideTrack, Sept 2021 Vol. 13 No. 17

"Tips for an Effective Business Succession Plan"
State Bar of Wisconsin Business Law Blog
August 19, 2020

Wisconsin Exhibit to "Executing Estate Planning Documents During the Pandemic and the Slow Return to the “New Normal”" by Martin M. Shenkman, Esq., Jonathan Blattmachr, Esq., Andrew Wolfe, Esq., and Thomas A. Tietz, Esq
LISI Estate Planning Newsletter #2799 (June 11, 2020)

"SECURE Act: Ensuring Safety of Retirement Accounts"
Wisconsin Lawyer Magazine
May 2020

"Estate Tax Returns for Nontaxable Estates After the Tax Cuts and Jobs Act of 2017"
Wisconsin Institute of CPAs' On Balance Magazine
May/June 2020

"A Powerful Tool: Modification or Termination of a Noncharitable Irrevocable Trust by Consent Under Section 411(A) of the Uniform Trust Code"
The American College of Trust and Estate Counsel
ACTEC Law Journal, Volume 45, Number 1, Fall 2019

Maureen has been ranked 10 out of 10 by Avvo:
Avvo is a national attorney rating service that uses a mathematical model to rate attorneys based on experience, professional achievements, industry recognition and professional conduct.

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FIND US O’Leary-Guth Law Office, S.C.
1251 W. Glen Oaks Lane, Mequon, WI 53092
CALL US P: (262) 238-6996
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