Alphabetically Union List - U
- U&T Thailand Workers Union
- U-Shin Thailand worker's union
- UAS Workers Union
- Udom Suk Hotel Workers Union
- Udorn Thani Workers Union
- Uea Wittaya Labour Union
- Ueno Chemicals Labour Union
- Ultra Sink and Go Labour Union
- Ultra Sink Labour Union
- Umbrella Producer Labour Union of Thailand
- Underware Maker Labour Union
- Uni Thai Shipyard Engineering Workers Union
- Uni-Sharm Workers Union
- Unico Workers Union
- Union of Colgate Employee Thailand
- Union of Producers and Sevice Providers
- Union Paper Workers Union
- Unocal Thailand Labour Union
- UOB Rattanasin Bank Workers Union
- Uthopian Workers Union
