These professional services firms in Ireland are mostly large, well-established companies, with a significant number operating globally. ICON plc specializes in accelerating the development of drugs, while Version 1 provides IT services and solutions. Cpl is a global provider of talent solutions, and Linesight offers professional consultancy to the construction industry. Matheson LLP, founded in 1825, is a global legal services provider.
The data shows a strong concentration of headquarters in Dublin, indicating a central hub for professional services in Ireland. While a mix of sectors is present, there is a notable presence of IT services, consulting, and financial services, reflecting a diverse professional landscape.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
ICON plciconplc.com
A global company founded in Ireland in 1990, specializing in accelerating the development of drugs and devices to save lives and improve quality of life |
35,001 | |||
| 2 |
ICON Strategic Solutionsiconplc.com
Global leader in Functional Service Provision services, offering cost-saving FSP models and clinical expertise to improve business performance Providing industry insights and job opportunities |
7,496 | |||
| 3 | 4,748 | ||||
| 4 |
PM Grouppmgroup-global.com
Specializes in designing, constructing, and commissioning high-tech facilities for pharma, food, data centers, medical technology, manufacturing, and energy sectors globally. |
4,477 | |||
| 5 |
Version 1version1.com
IT services and solutions provider trusted by global brands, offering independent advice to navigate the evolving IT landscape and drive customer success |
3,944 | |||
| 6 |
KPMG Irelandkpmg.ie
A leading provider of audit, tax, and advisory services for domestic and international clients across all sectors, specializing in driving value and navigating change |
2,978 | |||
| 7 |
Grant Thornton Irelandgrantthornton.ie
Providing innovative financial and business solutions with local expertise and global reach, fostering client relationships and ethical practices. |
2,514 | |||
| 8 |
PwC Irelandpwc.ie
Global network providing assurance, advisory, and tax services with a commitment to quality and building trust in society. |
2,502 | |||
| 9 |
S&W Irelandswgroup.com
Providing expert tax, accountancy, assurance, and advisory services to support Irish and international businesses through growth, risks, and exits. |
2,293 | |||
| 10 |
Linesightlinesight.com
Provides professional consultancy, management support, and strategic advice to the global construction industry from concept to completion across diverse sectors worldwide. |
1,931 | |||
| 11 |
Waystonewaystone.com
Global provider of governance, administration, risk, and compliance services supporting institutional investors and asset managers in managing investment structures. |
1,610 | |||
| 12 |
Deloitte Irelanddeloitte.com
Global professional services network delivering solutions and insights to address complex business challenges, with leadership capabilities, experience, and collaboration with clients |
1,594 | |||
| 13 |
Morgan McKinleymorganmckinley.com
Global talent services expert providing recruitment, executive search, and talent acquisition solutions across multiple professional disciplines worldwide. |
1,430 | |||
| 14 |
Matheson LLPmatheson.com
A global legal services provider with expertise in various practice areas, serving internationally focused companies and financial institutions operating in Ireland |
1,139 | |||
| 15 |
A&L Goodbody LLPalgoodbody.com
A leading Irish corporate law firm with over 100 years of experience, serving domestic and international businesses with offices in multiple locations |
1,054 | |||
| 16 |
CluneTechclunetech.com
Experienced in global payroll, tax returns, promotional management, and cross-border payments Award-winning and innovative financial solutions for multinational corporations |
1,021 | |||
| 17 |
First Derivativefirstderivative.com
Provides financial services organizations with data-driven and technology-enabled solutions to navigate digital transformation, improve operations, and manage risk, fostering growth and innovation. |
977 | |||
| 18 |
OSSosscompany.ie
This company offers HR expertise and recruitment solutions for the construction industry and events sector, focusing on quality, safety, and operational excellence |
951 | |||
| 19 |
Arthur Cox LLParthurcox.com
Leading law firm in Ireland and beyond, offering comprehensive corporate and business law services to international clients with over 100 years of progressive experience |
915 | |||
| 20 |
ICDS Groupicds.ie
Specializing in staffing solutions for Construction, Civil, Manufacturing, Engineering, Scientific, Medical, Technical, Food, IT, and Finance industries worldwide since 1976 |
858 | |||
| 21 |
Business Services Organisation (BSO)bso.hscni.net
Provider of business support functions and professional services for the Health and Social Care sector in Northern Ireland, offering career opportunities and comprehensive benefits |
844 | |||
| 22 |
Vistatecvistatec.com
A global provider of content solutions, specializing in localization, translation, digital marketing, technical documentation, multimedia, and language automation since 1997 |
796 | |||
| 23 | 
My Officemyoffice.ie
Providing affordable bookkeeping and administration services for businesses, helping them be more efficient and save time and money |
748 | |||
| 24 |
Forvis Mazars In Irelandforvismazars.com
provides audit, tax, consulting, financial advisory, corporate finance, and outsourcing services to international corporates, SMEs, financial institutions, and public bodies |
739 | |||
| 25 |
DOCSiconplc.com
It is a global leader in Functional Service Provision, offering expertise and models that enhance business performance and reduce costs. |
734 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 26 | 724 | ||||
| 27 |
Mason Hayes & Curran LLPmhc.ie
Leading law firm in Dublin, with global reach, specializing in energy, technology, finance, construction, and healthcare sectors, offering progressive career opportunities and commitment to social responsibility |
722 | |||
| 28 | 720 | ||||
| 29 |
Carne Groupcarnegroup.com
Provides a unified platform for risk, compliance, due diligence, distribution, and governance to simplify asset management operations. |
712 | |||
| 30 |
TTM Healthcare Groupttmhealthcare.ie
Specialists in healthcare talent management, healthcare process outsourcing & workforce solutions, placing professionals in frontline roles & supporting back-office operations with tailored solutions |
694 | |||
| 31 |
McCann FitzGerald LLPmccannfitzgerald.com
A leading law firm in Ireland with 400 lawyers, offering full services to corporate clients, financial institutions, and international organizations with offices in Dublin, London, New York, and Brussels |
657 | |||
| 32 |
APCapprocess.com
This company helps biopharma companies accelerate drug development with breakthrough science, lightning-fast process development, and radical collaboration to deliver for patients faster |
648 | |||
| 33 |
LotusWorkslotusworks.com
LotusWorks is an expert engineering partner specializing in Commissioning, Calibration, Engineering Services, Operations, and Maintenance for leading manufacturers and critical facilities |
634 | |||
| 34 |
Access Healthcareaccesshealthcare.ie
A healthcare staffing agency focused on understanding and serving nurses and clients, with a high fill rate for nursing shifts |
612 | |||
| 35 |
WILLIAM FRY LLPwilliamfry.com
A leading Irish law firm with extensive legal and tax expertise, serving domestic and international clients with a focus on achieving results through personalized service and practical solutions |
576 | |||
| 36 | 569 | ||||
| 37 |
Clarity Locums Ireland - Healthcare Recruitment Specialistsclaritylocums.com
Established in 2012, we provide trusted healthcare staffing services in Ireland and the UK, offering cost-effective solutions for professionals and clients |
546 | |||
| 38 |
Sherry FitzGeraldsherryfitz.ie
A leading property advisory firm in Ireland, offering a full range of services nationwide, backed by a team of talented professionals and trusted market insights |
534 | |||
| 39 |
BDO Irelandbdo.ie
BDO Ireland offers personalized services with a human touch, providing practical solutions with intelligence, empathy, and purpose through a global network |
527 | |||
| 40 |
Perigordperigord-as.com
Global leader in end-to-end packaging supply chain solutions for the Life Science Industry, specializing in artwork, marcoms, and digital assets |
501 | |||
| 41 |
Nearformnearform.com
A team of engineers, designers, and strategists building digital capabilities and solutions for enterprises, modernizing organizations with innovative platforms and systems |
497 | |||
| 42 |
Locumotion Irelandlocumotion.com
This company supports employers and GP doctors in building a sustainable primary healthcare infrastructure in Ireland, offering diverse career opportunities |
489 | |||
| 43 |
RECRUITERSrecruiters.ie
A trusted recruitment partner in Ireland, specializing in various industries such as sales, IT, finance, HR, and business operations |
464 | |||
| 44 |
Integrity360integrity360.com
Leading cyber security specialist in Europe, offering a range of services to identify, protect, detect, and respond to cyber risks for mid-market and enterprise organizations |
460 | |||
| 45 |
MKOmkoireland.ie
Ireland's largest Planning and Environmental consultancy with 200+ professionals delivering complex projects, adding value through multi-disciplinary expertise, and nationwide experience |
447 | |||
| 46 |
CAE Parc Aviationcae.com
A global aviation services company offering flight crew, aircraft support, MRO services, and job opportunities in various roles within the industry |
428 | |||
| 47 |
ESB Internationalesbinternational.ie
A global engineering consultancy firm serving the utility sector, specializing in delivering large-scale projects to maximize investor returns and minimize project risk |
413 | |||
| 48 | 409 | ||||
| 49 |
Excel Recruitmentexcelrecruitment.com
Excel Recruitment provides talented workforce solutions across various industries, specializing in Retail, IT, Hospitality, Healthcare, and more, with a track record of industry recognition and awards |
391 | |||
| 50 |
Servisourceservisource.ie
A fast-growing recruitment agency in Ireland providing temporary, permanent, and healthcare services along with a range of HR solutions and training courses |
380 | |||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 12, 2026.
More company lists in Ireland
- The largest companies in Ireland 1,769
- Multinational companies in Ireland 564
- SaaS companies in Ireland 203
- Software Development companies in Ireland 176
- Retail chains in Ireland 166
- Financial services firms in Ireland 143
- Financial Services companies in Ireland 143
- Manufacturers in Ireland 125
- Companies with in-house R&D in Ireland 120
- Critical infrastructure operators in Ireland 118
- Companies with a mobile app in Ireland 99
- Public sector organisations in Ireland 88
- Retail companies in Ireland 84
- Education providers in Ireland 83
- IT Services and IT Consulting companies in Ireland 83
- IT services companies in Ireland 77
- Construction companies in Ireland 70
- Healthcare providers in Ireland 69
- Consulting firms in Ireland 65
- Family-owned companies in Ireland 64
- Distributors and wholesalers in Ireland 63
- Subscription businesses in Ireland 62
- Hardware manufacturers in Ireland 61
- Government Administration companies in Ireland 57