The charges relate relate to Thomas' conduct while playing in the franchise-based Lanka Premier League (LPL, the Abu Dhabi T10 and the Caribbean Premier League (CPL).
The 33-year-old has represented West Indies in all three formats, appearing in 21 ODIs, 12 T20Is and one Test match, and was named in the squad for next month's ODI series against the United Arab Emirates.
The ICC said in a media statement: "The charges involve contriving or being party to an agreement to fix or attempt to fix, contrive or influence improperly the result, progress, conduct or other aspects of matches in the Lanka Premier League 2021.
"He has also been charged under several other codes, including failing to disclose full details of an approach in the Lanka Premier League 2021, Abu Dhabi T10 2021 and CPL 2021."
Cricket West Indies (CWI) said it would fully support the ACU investigation and that it was resolute about "denouncing corruption" in cricket.
"CWI (Cricket West Indies) is not directly involved in the process but remains firm in denouncing corruption in cricket, and fully supports the ICC ACU (Anti-Corruption Unit) in its efforts to uphold the integrity of the sport," the body said.
"In collaboration with ICC and the West Indies Players Association (WIPA), CWI remains committed to sensitising and educating our players and officials on anti-corruption in sports."
Thomas has 14 days to respond to the charges.