Top Climate tech companies
Companies decarbonising power, transport, agriculture, and industry.
Ranked by current headcount across the largest Climate tech companies. Refreshed daily.
- 1Bureau Veritas· Courbevoie, Île-de-France, France
- Post-IPO debt
- 56.1k employees
- 2Veolia· Aubervilliers, Île-de-France, France
- Post-IPO debt
- 48.4k employees
- 3WM· Houston, Texas, United States
- Post-IPO debt
- 27.5k employees
- Founded 1968
- 4SUEZ· Labretonie, Nouvelle-Aquitaine, France
- 26.1k employees
- Founded 2008
- 5Republic Services· Phoenix, Arizona, United States
- 20.7k employees
- Founded 1998
- 6Siemens Gamesa· Zamudio, Basque Country, Spain
- Post-IPO debt
- 20.1k employees
- Founded 2017
- 7GE Power· Schenectady, New York, United States
- 17.5k employees
- Founded 1992
- 8EQUANS· Courbevoie, Île-de-France, France
- 15.1k employees
- Founded 2021
- 9Eiffage Énergie Systèmes· Vélizy-Villacoublay, Île-de-France, France
- 14.9k employees
- 10Dalkia· Saint-André-Lez-Lille, Hauts-de-France, France
- 14.4k employees
- Founded 1937
- 11Clean Harbors· Norwell, Massachusetts, United States
- Post-IPO debt
- 13k employees
- Founded 1980
- 12SPIE· France
- Post-IPO debt
- 12.6k employees
- Founded 1990
- 13Veolia | Water Tech· Aubervilliers, Île-de-France, France
- 12.4k employees
- 14Rentokil Initial· Crawley, England, United Kingdom
- Post-IPO equity
- 12.3k employees
- Founded 1925
- 15Sabesp· Brazil
- Post-IPO debt
- 12k employees
- Founded 1973
- 16RSK Group· Helsby, England, United Kingdom
- Private equity
- 12k employees
- Founded 1989
- 17Grupo Tragsa· Madrid, Community of Madrid, Spain
- 12k employees
- Founded 1977
- 18Comisión Federal de Electricidad· Mexico
- 11.9k employees
- Founded 1937
- 19Equans France· Courbevoie, Île-de-France, France
- 10.7k employees
- 20Environment Agency· Bristol, England, United Kingdom
- 10.1k employees
- Founded 1996
- 21MANN+HUMMEL· Ludwigsburg, Baden-Württemberg, Germany
- 9.6k employees
- Founded 1941
- 22Apave· Courbevoie, Île-de-France, France
- 9.3k employees
- 23ALTRAD· Montpellier, Occitanie, France
- Debt
- 8.7k employees
- Founded 1985
- 24GFL Environmental Inc.· Concord, Ontario, Canada
- Post-IPO debt
- 8k employees
- Founded 1995
- 25Pizzaria· Brazil
- 7.4k employees
- Founded 2015
Find engineers and designers at top Climate tech companies
The Climate tech industry runs on the people who build it. The list above ranks the largest Climate tech companies by current headcount, drawn from public LinkedIn and Crunchbase records. Across the 16,509 Climate techcompanies in our index, you’ll find software engineers, ML researchers, designers, founders, and recruiters worth talking to — whether you’re hiring, investing, or doing market research.
Each company on the list is a hub of talent. The biggest Climate tech companies tend to attract specialised engineers, while younger ones run on small founding teams and hire generalists. Looking at headcount, last funding round, and HQ location side by side gives you a quick read on where the talent density is highest.
Refolk turns this list into a search. Ask for “Climate techengineers in San Francisco hiring senior ML” or “designers at Climate techcompanies who shipped a product in 2025” and Refolk returns a fresh ranked shortlist with the sources that earned each person a spot.
How this list is built
Last refreshed: Thu, 07 May 2026 05:55:21 GMT
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