This selection of large companies with in-house R&D in Ireland includes several global players in manufacturing and services. Among them are Johnson Controls, a leader in smart building solutions, and Eaton, which focuses on intelligent power management. Also present are Smurfit Westrock and Smurfit Kappa, both major providers of paper-based packaging, and TE Connectivity, specializing in connectivity and sensor solutions. ICON plc is highlighted for its role in accelerating drug development.
A notable characteristic of these companies is their diverse industry representation, ranging from industrial machinery and electrical manufacturing to biotechnology research and food and beverage services. The data indicates a concentration of headquarters in Dublin, with Cork, Galway, Naas, Dundalk, and Kilkenny also hosting significant operations. Most of these companies are large, well-established firms with substantial employee bases.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Johnson Controlsjohnsoncontrols.com
Global leader in transforming environments through smart, healthy, and sustainable buildings Offering innovative digital solutions for various industries worldwide |
67,718 | |||
| 2 | 51,011 | ||||
| 3 |
Smurfit Westrocksmurfitwestrock.com
Global provider of innovative paper-based packaging solutions with extensive operations, mills, and a large workforce across multiple countries. |
50,141 | |||
| 4 |
Smurfit Kappasmurfitwestrock.com
A global provider of sustainable paper-based packaging solutions, offering innovative products and expertise to drive success for customers worldwide |
48,000 | |||
| 5 |
TE Connectivityte.com
A global leader in industrial technology manufacturing, specializing in connectivity and sensor solutions for various industries to create a safer, sustainable, and connected future |
41,478 | |||
| 6 |
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 | |||
| 7 |
Weatherfordweatherford.com
A global energy services company with 17,000 team members in 75 countries, providing solutions for the challenges of the energy industry |
29,301 | |||
| 8 | 16,755 | ||||
| 9 |
Cimpresscimpress.com
Cimpress plc invests in mass-customization businesses, providing personalized products to meet individual customer needs with near mass production efficiency |
12,460 | |||
| 10 |
Allerganabbvie.com
The company discovers and delivers innovative medicines in various therapeutic areas including immunology, oncology, neuroscience, eye care, and more |
9,833 | |||
| 11 |
University College Corkucc.ie
Established in 1845 as a part of Queen's University, now a founding member of National University of Ireland Offers higher education with rich heritage |
7,328 | |||
| 12 |
Allegionallegion.com
Global leader in seamless access solutions for homes, businesses, schools, and institutions, specializing in securing people and assets around the door |
7,123 | |||
| 13 |
Perrigo Company plcperrigo.com
European Consumer Self-Care market top player, U.S. store brand over-the-counter and infant formula provider, offering trusted health and wellness solutions. |
5,088 | |||
| 14 |
Glanbiaglanbia.com
A global nutrition company creating better products, sustainable practices, and high-quality nutrition to help people live full, healthy lives |
4,176 | |||
| 15 |
Jazz Pharmaceuticalsjazzpharma.com
Global biopharmaceutical company focused on developing innovative medicines for serious diseases with limited treatment options to improve patient lives. |
3,643 | |||
| 16 |
Mallinckrodt Pharmaceuticalsmnk.com
Specializing in specialty pharmaceuticals, we develop, manufacture, and distribute innovative treatments for underserved patient populations across various medical fields |
3,400 | |||
| 17 |
Tyco SimplexGrinnelltycosimplexgrinnell.com
A global leader in fire protection, security, HVAC, building controls, and energy storage, delivering customized solutions to meet customers' needs |
3,232 | |||
| 18 |
Atlantic Technological Universityatu.ie
A new Technological University in the West and North-West of Ireland, offering programs across multiple campuses and embracing innovation for the future |
2,966 | |||
| 19 |
Kingspan Groupkingspan.com
Global leader in high-performance insulation and building envelope solutions for construction, aiming to improve building performance and create a sustainable future |
2,910 | |||
| 20 |
St James's Hospital Dublinlinkin.bio
An academic teaching hospital delivering health treatment, care, and diagnosis while prioritizing education, research, and collaboration with a focus on quality and accountability |
2,788 | |||
| 21 | 2,720 | ||||
| 22 |
Alkermesalkermes.com
A neuroscience-focused company developing innovative medicines for psychiatric and neurological disorders, with a strong focus on patient well-being and community support |
2,397 | |||
| 23 |
St. Vincent's University Hospitalstvincents.ie
A leading academic teaching hospital providing acute, chronic, and emergency care across 50 medical specialties with international accreditation and pioneering patient care approaches |
2,000 | |||
| 24 |
Teagascteagasc.ie
This organization provides research, advisory, and training services to the agriculture and food industry, as well as rural communities in Ireland |
1,760 | |||
| 25 |
MSD Irelandmsd-ireland.com
A leading biopharmaceutical company dedicated to inventing life-saving medicines and vaccines for challenging diseases, with a focus on research and improving health worldwide |
1,697 | |||
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 |
Kepak Groupkepak.com
Irish-based meat processor with multiple facilities, producing fresh and value-added meat products for international foodservice and retail markets. |
1,409 | |||
| 27 |
IPLiplschoeller.com
A top packaging provider offering sustainable solutions for various industries including food, consumer, agriculture, logistics, and the environment |
1,208 | |||
| 28 |
AMCS Groupamcsgroup.com
Global leader in integrated software and vehicle technology for environmental, waste, recycling, and EHSQ industries, improving efficiency, margins, and customer service |
1,165 | |||
| 29 |
Tirl谩ntirlan.com
A world-class food and nutrition business with a diverse portfolio of products for consumer, agri, and international markets, focusing on sustainability and innovation |
1,095 | |||
| 30 |
Anord Mardixanordmardix.com
Global leader in critical power distribution and protection, offering bespoke solutions and innovative products Part of a $24B diversified manufacturer |
1,074 | |||
| 31 |
Technological University of the Shannontus.ie
Higher education institution with six campuses across Ireland, providing diverse academic programs and vibrant student experiences to over 14,000 students. |
1,020 | |||
| 32 |
Maynooth Universitymaynoothuniversity.ie
A research-intensive university in Ireland focused on commercialization, enterprise, and social responsibility Offers modern facilities for collaborative research and business incubation |
1,007 | |||
| 33 |
FINEOSfineos.com
Leading provider of core systems for life, accident, and health insurers globally, offering end-to-end SaaS products for quote to claim administration, digital engagement, and analytics |
838 | |||
| 34 |
Creganna Medicalte.com
A global leader in designing and manufacturing access & delivery devices for minimally invasive medical therapies with a reputation for industry innovation and quality |
790 | |||
| 35 |
Devexpertsdevexperts.com
Devexperts specializes in developing complex software solutions for the Capital Markets industry, including trading platforms, market data products, and consulting services |
786 | |||
| 36 |
Wrightbuswrightbus.com
A family-run business manufacturing iconic electric buses, leading the way in zero-emission transportation with innovative solutions and environmental awareness |
785 | |||
| 37 |
Moog Controls Corporation (Philippine Branch)moog.com
A worldwide designer and integrator of precision motion control products and systems for various industries, with a strong focus on culture and integrity |
779 | |||
| 38 |
Aerogenaerogen.com
Aerogen innovates aerosol drug delivery to improve respiratory care, patient outcomes, and healthcare provider efficiency, focusing on safety and effectiveness |
698 | |||
| 39 |
Fenergofenergo.com
Develops SaaS financial technology solutions for client lifecycle management, regulatory compliance, risk monitoring, operational efficiency, and digital transformation in financial institutions. |
695 | |||
| 40 |
Limerick Institute of Technologylit.ie
Offers higher education across five campuses and a learning center, providing courses from certificate to PhD levels, including craft apprenticeships and adult education. |
694 | |||
| 41 |
Glen Dimplexglendimplex.com
Manufacturing heating, ventilation, flame, precision cooling, and consumer appliances with innovative solutions to improve everyday life and energy efficiency. |
664 | |||
| 42 |
Bimedabimeda.com
An international veterinary pharmaceutical company with manufacturing facilities in multiple countries, offering high-quality products worldwide and focused on customer satisfaction |
661 | |||
| 43 |
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 | |||
| 44 |
Mary Immaculate College, Irelandmic.ul.ie
An established university-level college providing education in liberal arts, early childhood care, and professional development programs with state-of-the-art facilities in Limerick |
647 | |||
| 45 |
Technological University of the Shannon, Athlone Campustus.ie
Ireland's new technological university with 14,000+ students on six campuses, offering vibrant student experiences in Athlone, Limerick, Thurles, Clonmel, and Ennis |
617 | |||
| 46 |
Vital Healthcaredccvital.com
A healthcare company specializing in sales, marketing, and distribution of pharmaceuticals, medical, surgical, and lab products with a focus on improving patient care |
571 | |||
| 47 |
Chanelle Pharmachanellepharma.com
Ireland鈥檚 largest manufacturer of generic pharmaceuticals for human and animal health, with a global presence and ambitious plans for growth |
559 | |||
| 48 |
Mergon Groupmergon.com
Manufacturer of high-quality plastic components for automotive, medical, and industrial products, serving global brands with innovative design and sustainable solutions |
533 | |||
| 49 |
Nearformnearform.com
A team of engineers, designers, and strategists building digital capabilities and solutions for enterprises, modernizing organizations with innovative platforms and systems |
497 | |||
| 50 |
Munster Joinerymunsterjoinery.ie
Large manufacturer of energy efficient windows and doors in Europe, with operations in Ireland, Northern Ireland, and the UK serving international markets |
452 | |||
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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.
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- 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
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- Professional services firms in Ireland 126
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- Companies with a mobile app in Ireland 99
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- Government Administration companies in Ireland 57