Ong Ken Loon

Ken Loon has worked on a number of tax litigation cases that have led to landmark case law, including:

1. AQQ v Comptroller of Income Tax [2011] SGITBR 1 in which she appealed against the decision of the Income Tax Board of Review.


2. Lai Ling Wan (alias Lai Lily) v Commissioner of Stamp Duties [2011] 4 SLR 845 in which she successfully represented the appellant in the High Court in overturning the position taken by the Commissioner of Stamp Duties in his administrative circular on multiple property purchases.


3. Comptroller of Income Tax v MT [2006] 3 SLR(R) 688 in which she successfully represented a  ship owner before the Income Tax Board of Review and the High Court in tax exemption on the bareboat charter fees of a Singapore-registered ship.


4. First DCS Pte Ltd v. Chief Assessor and Comptroller of Property Tax [2007] 3 SLR 326; Chief Assessor and Another v First DCS Pte Ltd [2008] 2 SLR 724 in which she represented the Chief Assessor before the High Court and Court of Appeal in the assessment of pipelines running through land owned by third parties.

Chambers Asia-Pacific
Tax 2024 – Band 1; Leading lawyer for 12 consecutive years

"It's great working with Ken Loon."

"Ken Loon shines especially in having the nous to pull in subject matter and local law legal experts early, seeing around corners for us, to create holistic, battle-tested and well-precedented advice in solving complex problems. She clearly loves her work and it shows through in the quality and speed of delivery."

"She provides calm yet technically strong and pragmatic counsel while under challenging deadlines and pressures."

Ken Loon is “well noted for her dispute resolution expertise and boasts enviable experience handling tax litigation matters.”

“She is sought after by a wide range of clients to handle tax investigations as well as private client work.”

“very practical, very smart and absolutely amazing.”

“She is very solution-driven and extremely diligent in her response and advice.”

She is sought after for her depth of experience in handling tax disputes initiated by the tax authorities. "She is a lawyer I would go to for technical matters." 

Peers note her ability in tax litigation, while a client notes "her advice is very clear and understandable." 

Interviewees describe her as “technically strong” and praised her ability to “empathise with clients’ needs.”

Sources describe Ken Loon as "responsive, on the ball and very sound" and "very calm and composed: when she's in court, she clearly knows what she's doing."

Clients also praise Ken Loon for her pragmatic approach, stating: "We have been given clear advice and provided with support."

Another market source was similarly impressed, describing her as "commercially savvy and very prompt."

Asia-Pacific Legal 500 
Tax 2024 – Hall of Fame for 5 consecutive years, previously a Leading Individual for 8 consecutive years

Private Wealth and Family Law 2024 – Recommended Lawyer for 7 years

“She is very experienced and knows the people working in IRAS very well including their backgrounds, the experience, how they work and how they are likely to treat your case. She is able to read the government’s approach to tax issues and can also be a useful contact if you have a difficult issue with the government.”

“Her advice is always practical in approach and always sound. In terms of legal research, she is an extremely conscientious lawyer who always does her homework and her numbers and she is always prepared and able to clearly explain the tax impact of the various options so that it is easy to determine which to go for. In terms of negotiations and communications, you cannot get better than Ken Loon as she always knows how to put the arguments across and she is extremely clear and concise.’”

A client commended Ken Loon for her “strong technical skills.”

Ong Ken Loon is a "go-to person for any tax dispute work" and particularly rated for her "professionalism and knowledge".

Asialaw Leading Lawyers
Tax 2023/2024 – Distinguished Practitioner for 5 consecutive years

Clients describe Ken Loon as “very knowledgeable” and she has “calm hands.”

International Tax Review World Tax
Tax Controversy Leaders 2023 – Highly Regarded for 10 consecutive years
Women in Tax Leaders 2023 – Highly Regarded for 8 consecutive years

“Well-respected specialist in tax dispute resolution and regularly represents clients in tax tribunals and courts.”

ALB Asia’s Top 15 Female Lawyers
Identified by Asia Legal Business as one of the top 15 female lawyers in Asia in the inaugural list in 2021

Women in Business Law Expert Guide
World’s leading female lawyers in 2021

Best Lawyers International: Singapore
Tax Law 2025 – Endorsed individual for 6 consecutive years
Trusts and Estates 2024 – Endorsed individual for 5 consecutive years

Who’s Who Legal
Global Leader​
Corporate Tax: Advisory 2022 – Leading Lawyer for 2 consecutive years
National Leader
Southeast Asia: Corporate Tax 2023 – Recommended individual for 2 consecutive years

"An approachable and patient practitioner at break down legal terms to laymen"

Asia Women In Business Law Awards
Singled out as the most outstanding practitioner in the field of Tax Dispute Resolution in 2019

Asia Legal Awards
Tax Lawyer of the Year 2018

Singapore Business Review
Singapore’s 40 most influential lawyers aged 40 and under in 2015 – Listed lawyer

Practical Law Company Which Lawyer?
Private Client 2012 – Recommended lawyer for 3 consecutive years

• Member, Law Society of Singapore
• Member, Singapore Academy of Law
• Member, Criminal Law Advisory Committee (Hearing)
• Member, International Fiscal Association, Singapore Branch
• Member, Singapore International Chamber of Commerce, Tax Interest Policy Group
• Accredited Tax Advisor (Income Tax) in Singapore Chartered Tax Professionals Limited