Teresa is a strong advocate for her employment law, civil rights and municipal liability clients. In her role as an experienced litigator, Teresa represents school districts, school leaders, municipalities, police departments and various non-profit and corporate entities, in claims made and suits brought against them. She appears regularly in both the state and federal courts, representing clients in suits brought against them involving Section 1983 claims, Title VII actions, ADEA, ADA, FMLA and PHRA matters.
When called on to represent and defend school leaders and school districts, Teresa’s experience and understanding in education law serve her clients well. She represents all types of education clients with a focus on Special Education Law, Due Process Student Rights, Bullying and Anti-Bullying Policies and Educator Due Process.
In addition to her experience as a litigator, Teresa represents employers and other professionals in various administrative matters; before the Pennsylvania Labor Relations Board, the National Labor Relations Board, the Pennsylvania Human Relations Commission, the Equal Employment Opportunity Commission, and multiple other administrative units including the Pennsylvania Department of Education, the Office for Dispute Resolution, the Office for Civil Rights and the State Ethics Commission. Teresa also consults with employers, school leaders and various types of public entities on matters including auditing, updating and revising personnel manuals and educational policies.
A member of the Allegheny County Bar Association, Teresa is recognized among The Best Lawyers in America for 2024 and 2025 in the areas of Litigation - Labor and Employment and was recognized as a Best Lawyer in 2025 in the area of Employment Law - Management. Notably, Teresa was also recently inducted as a fellow of the Academy of Trial Lawyers of Allegheny County, a community of trial lawyers committed to improving the civil trial process, preserving the jury system and enhancing the quality of trial advocacy in Allegheny County. Fellows must have significant trial experience and exhibit the highest levels of ethical standards and professionalism.
Teresa is admitted to practice before the United States District Court for the Western District of Pennsylvania and all Pennsylvania state courts.
Honors & awards
The Best Lawyers in America, Education Law
2026
The Best Lawyers in America, Employment Law - Management
2025-2026
The Best Lawyers in America, Litigation - Labor and Employment
2024-2026
Pennsylvania Super Lawyer Rising Star
2013
Year joined
2000
Thought Leadership
98 Marshall Dennehey Attorneys Recognized in the 2026 Editions of The Best Lawyers in America and the Best Lawyers: Ones to Watch in America
August 20, 2025
Marshall Dennehey is proud to highlight the firm’s 98 attorneys who have been recognized in the 2026 editions of The Best Lawyers in America and the Best Lawyers: Ones to Watch in America. Less than 6% of all practicing lawyers in the U.S.
Legal Update for Special Education Law - Case Law Update
Pittsburgh
Harrisburg
School Leaders' Liability
July 1, 2025
U.S. Supreme Court Clarifies Standard for Disability Discrimination Claims in Education Under Section 504 and ADA Legal Update for Special Education Law - July 2025 is prepared by Marshall Dennehey to provide information on recent legal developments of interest to
Teresa O. Sirianni Elected to Membership of the Academy of Trial Lawyers of Allegheny County
Public Entity & Civil Rights Litigation
Employment Law
School Leaders' Liability
July 31, 2024
Teresa O.
Legal Update for Special Education Law - Updates from the Pennsylvania Department of Education
Pittsburgh
School Leaders' Liability
June 1, 2024
Commonwealth Court voids Pennsylvania Department of Education’s newly imposed Age-Out Plan for failure to implement it in accordance with Pennsylvania Laws.* Legal Update for Special Education Law - June 2024
Legal Update for Special Education Law - Updates from the Pennsylvania Department of Education
Pittsburgh
School Leaders' Liability
April 1, 2024
Effective November 1, 2023, the Prior Written Notice for a Reevaluation and Request for Consent form were separated into into different forms, the Prior Written Notice for a Reevaluation form and the Request for Consent for a Reevaluation form.
Classes/Seminars Taught
A Primer on Pursuing and Defending Remedies and Damages, The Annual Allegheny County Bar Association's Labor and Employment Symposium, November 14, 2024
Employment Claims Involving Law Enforcement: Prepare to Defend, The Western Pennsylvania Chiefs’ of Police Association, November 19, 2021
Effective Practices for General Educators in Inclusive Classrooms, November 18, 2018
The Role of the General Educator in the Special Education Process, January 15, 2018
How A Student Can Make A Successful Return to School - Liabilities and Responsibilities - Concussion Presentation, February 28, 2014
Employment Liability in the Cyber Age, Marshall Dennehey / AIG Employment Seminar, Pittsburgh, PA, May 2, 2013
Employment in Crisis: Workplace Security & Lessons from the Sandusky Case, Marshall Dennehey, Erie, PA, October 11, 2012
Speaker on various topics involving employment claims and federal practice.
AV Preeminent®: The highest peer rating standard. This rating signifies a large number of the lawyer’s peers rank him
or her at the highest level of professional excellence for their legal knowledge, communication skills and ethical standards.
Distinguished: An excellent rating for a lawyer with some experience. This rating indicates the attorney is widely
respected by their peers for high professional achievement and ethical standards.
Notable: This rating indicates that the lawyer has been recognized by a large number of their peers for strong ethical standards.
