Refolk

Top Climate tech companies

Companies decarbonising power, transport, agriculture, and industry.

Ranked by current headcount across the largest Climate tech companies. Refreshed daily.

  1. 1
    Bureau Veritas· Courbevoie, Île-de-France, France
    • Post-IPO debt
    • 56.1k employees
  2. 2
    Veolia· Aubervilliers, Île-de-France, France
    • Post-IPO debt
    • 48.4k employees
  3. 3
    WM· Houston, Texas, United States
    • Post-IPO debt
    • 27.5k employees
    • Founded 1968
  4. 4
    SUEZ· Labretonie, Nouvelle-Aquitaine, France
    • 26.1k employees
    • Founded 2008
  5. 5
    Republic Services· Phoenix, Arizona, United States
    • 20.7k employees
    • Founded 1998
  6. 6
    Siemens Gamesa· Zamudio, Basque Country, Spain
    • Post-IPO debt
    • 20.1k employees
    • Founded 2017
  7. 7
    GE Power· Schenectady, New York, United States
    • 17.5k employees
    • Founded 1992
  8. 8
    EQUANS· Courbevoie, Île-de-France, France
    • 15.1k employees
    • Founded 2021
  9. 9
    Eiffage Énergie Systèmes· Vélizy-Villacoublay, Île-de-France, France
    • 14.9k employees
  10. 10
    Dalkia· Saint-André-Lez-Lille, Hauts-de-France, France
    • 14.4k employees
    • Founded 1937
  11. 11
    Clean Harbors· Norwell, Massachusetts, United States
    • Post-IPO debt
    • 13k employees
    • Founded 1980
  12. 12
    SPIE· France
    • Post-IPO debt
    • 12.6k employees
    • Founded 1990
  13. 13
    Veolia | Water Tech· Aubervilliers, Île-de-France, France
    • 12.4k employees
  14. 14
    Rentokil Initial· Crawley, England, United Kingdom
    • Post-IPO equity
    • 12.3k employees
    • Founded 1925
  15. 15
    Sabesp· Brazil
    • Post-IPO debt
    • 12k employees
    • Founded 1973
  16. 16
    RSK Group· Helsby, England, United Kingdom
    • Private equity
    • 12k employees
    • Founded 1989
  17. 17
    Grupo Tragsa· Madrid, Community of Madrid, Spain
    • 12k employees
    • Founded 1977
  18. 18
    • 11.9k employees
    • Founded 1937
  19. 19
    Equans France· Courbevoie, Île-de-France, France
    • 10.7k employees
  20. 20
    Environment Agency· Bristol, England, United Kingdom
    • 10.1k employees
    • Founded 1996
  21. 21
    MANN+HUMMEL· Ludwigsburg, Baden-Württemberg, Germany
    • 9.6k employees
    • Founded 1941
  22. 22
    Apave· Courbevoie, Île-de-France, France
    • 9.3k employees
  23. 23
    ALTRAD· Montpellier, Occitanie, France
    • Debt
    • 8.7k employees
    • Founded 1985
  24. 24
    GFL Environmental Inc.· Concord, Ontario, Canada
    • Post-IPO debt
    • 8k employees
    • Founded 1995
  25. 25
    Pizzaria· 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

Refolk pulled the largest companies in Climate tech from public LinkedIn and Crunchbase records, ranked them by current employee count, and kept those with at least 25 employees. The list refreshes once a day.

Last refreshed: Thu, 07 May 2026 05:55:21 GMT

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