Alphabetically Union List - K
- K Kattan Textile Workers Union
- Kalasin Seree Garment Workers Union
- Kamakassu Nawanakhon Workers Union
- Kang Yong Electric Labour Union of Thailand
- Kanjana Drinking Water Workers Union
- Kao Su Workers Union
- Karat Sanitary Workers Union
- Karon Villa Phuket Workers Union
- Kasikorn Bank Supervisory Labour Union
- Kasikorn Bank Workers Union
- Kate Thanakij Krua Narong Workers Union
- Kawasiki Automobile Thailand Workers Union
- Kawasumi Navanakhon Workers Union
- KCE Electronics Employees Union
- KCE Workers Union
- KDK Fujikura Workers Union
- Keo Workers Union
- Key Thai Workers Union of Thailand
- Khanom Electric Generation Executive Labour Union
- Khanom Electric Generation Workers Union
- Khemjira Transport Workers Union
- Kiat Charoen City Parts Workers Union
- Kiattanapiwat Labour Union
- Kijkamon Sukoson and Affiliated Workers Union
- Kimberly Clark Workers Union
- King Bo Tu Concept Workers Union
- Kingspan Workers Union
- Kitakawa (Thailand) Workers Union
- Kitch Thailand Workers Union
- Kitchen Utensil Workers Union
- KK Connection Labour Union
- KLM Employees Union of Thailand
- Klockner Thailand Workers Union
- KME Garment Workers Union
- KOBATECH THAILAND WORKER'S UNION
- Kobe Battery Workers Union
- Kobelco Supervisor Workers\' Union
- Kobelco Thailand Worker's Union
- Kobemickwire Workers Union of Thailand
- Kochin Workers Union
- Kohher (Thailand) Supervisory Labour Union
- Koito Workers Union
- Kor Siam Workers Union
- Korat Automotive Workers Union
- Korat Saison Workers Union
- Krirk Seree Workers Union
- Krung Thai Business Asset Transport Labour Union
- krungthai Bank State Enterprise Labour Union
- Krungthai Bank Supervisory Labour Union
- Kuang Hong Supervisory Labour Union
- Kuang Hong Workers Union
- Kumpawapi Sugar Workers Union
- Kwo Yu Ha Workers Union
- Kyokseki Labour union
