电子专业制造服务（EMS，Electronic Manufacturing Services），亦称ECM（Electronic Contract Manufacturing），中文又译为专业电子代工服务。相对于传统的OEM或ODM服务仅提供产品设计与代工生产，EMS厂商所提供的是知识与管理的服务，例如物料管理、后勤运输，甚至提供产品维修服务。
2019全球EMS代工厂50强榜单
1.Hon Hai Precision Industry (Foxconn )— New Taipei, Taiwan
2.Pegatron— Taipei, Taiwan
3.Flex— Singapore
4.Jabil— St. Petersburg, FL
5.Wistron–Taoyuan, Taiwan
6.Sanmina— San Jose, CA
7.Celestica— Toronto, Canada
8.New Kinpo Group— New Taipei, Taiwan
9.Universal Scientific Industrial Co.— Shanghai, China
10.Venture— Singapore
11.Plexus— Neenah, WI
12. Benchmark Electronics— Angleton, TX
13.Shenzhen Kaifa–Shenzhen, China
14. Zollner Elektronik Group— Zandt, Germany
15. SIIX— Osaka, Japan
16. Fabrinet–Pathumthani, Thailand
17. UMC Electronics— Saitama, Japan
18. Integrated Micro-Electronics, Inc.— Laguna, Philippines
19. Kimball Electronics Group— Jasper, IN
20. PKCGroup–Reeahe, Finland
21. V.S. Industry Berhad, Senai, Malaysia
22. Sumitronics— Tokyo, Japan
23. Asteelflash–Neuilly Plaisance, France
24. NEO Tech — Chatsworth, CA
25. VTech Communications— Hong Kong
26. Alpha Networks — Hsinchu, Taiwan
27.Enics AG,Zurich, Switzerland
28.Scanfil EMS— Sievi, Finland
29. 3CEMS–Guangzhou, China
30.VIDEOTON Holding— Székesfehérvár, Hungary
31. Creation Technologies— Burnaby, BC, Canada
32.Ducommun–St. Louis, Missouri
33. Katolec, Tokyo, Japan
34.Neways Electronics –Son, The Netherlands
35.Key Tronic— Spokane Valley, WA
36.WKK Technology Ltd.— Hong Kong
37.Wong’s, Hong Kong
38.Orient Semiconductor Electronics— Kaohsiung, Taiwan
39. éolane,Le Fresne Sur Loire, France
40.Computime Limited— Hong Kong
41. ALL CIRCUITS— Meung-sur-Loire, France
42.Sparton,Schaumber, Illinois
43.SVI, Bangkadi Pathumthani, Thailan
44.Valuetronics Holding — Hong Kong
45.LACROIX Electronics— Vern-sur-Seiche, France
46.SMT Technologies — Kedah, Malaysia
47.Hana Microelectronics— Bangkok, Thailand
48.Global Brands Manufacturing, New Taipei City, Taiwan
49.Fideltronik— Sucha Beskidzka, Poland
50.Kitron— Billingstad, Norway
