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Tetra Tech Inc number of employees

Tetra Tech Inc reported 25,000 employees at September 28, 2025 in its latest annual report, down 5,000 (16.7%) on the year before. That compares with 21,000 at October 3, 2021. Revenue per employee was $217,704.

Headcount by year

Fiscal year endEmployeesChangeRevenue per employeeSource
September 28, 2025 25,000 −5,000 (16.7%) $217,704 10-K, filed November 20, 2025
September 29, 2024 30,000 +3,000 (11.1%) $173,289 10-K, filed November 19, 2024
October 1, 2023 27,000 +6,000 (28.6%) $167,502 10-K, filed November 22, 2023
October 2, 2022 21,000 +0 (0.0%) $166,859 10-K, filed November 25, 2022
October 3, 2021 21,000 — $153,024 10-K, filed November 24, 2021

What the annual reports say

  • Leading with Science® also means fully leveraging the collective expertise provided by our global workforce of more than 25,000 associates. 2025 annual report
  • Leading with Science® also means fully leveraging the collective expertise provided by our global workforce of 30,000 associates. 2024 annual report
  • Leading with Science® also means fully leveraging the collective expertise provided by our global workforce of 27,000 associates. 2023 annual report
  • At fiscal 2022 year-end, we had approximate ly 21,000 staff worldwide. 2022 annual report
  • At fiscal 2021 year-end, we had approximate ly 21,000 staff worldwide. 2021 annual report

Headcount as the company states it in Item 1 of its annual report (some count full-time equivalents or exclude part-time and temporary staff), at the date it gives. Years where the report states no clear total are left out rather than estimated. Changes can reflect acquisitions and disposals as well as hiring and job cuts.

Compare with peers

Head to head: TRU vs TTEKNIQ vs TTEKPSN vs TTEKEFX vs TTEK

More: Research & Consulting Services stocks compared, Industrials sector, rankings of US companies

Figures from Tetra Tech Inc's SEC filings (10-K and 10-Q), retrieved October 20, 2026. How we read and check them: methodology and data sources. Not investment advice. Back to Tetra Tech Inc.