Thomas Greiss (born 29 January 1986) is a German professional ice hockey goaltender who currently plays for Löwen Frankfurt of the Deutsche Eishockey Liga.

[4] On 12 October 2010, just prior to the commencement of the 2010–11 season, Greiss was put on waivers by San Jose, eventually clearing and reporting to Worcester of the AHL.

[5] Nine days later, after failing to see any gameplay as Worcester's third-string goaltender, he was reassigned to Brynäs IF in the Swedish Elitserien to provide him regular playing time.

At the end of the 2013–14 season, he was not re-signed by the Coyotes, whereupon he signed a one-year, $1 million contract as an unrestricted free agent with the Pittsburgh Penguins on 1 July 2014.

[10] After the 2014–15 season in which he appeared in 20 games for the Penguins, Greiss once again switched teams as a free agent, signing with the New York Islanders on a two-year, $3 million contract on 1 July 2015.

[11] In March 2016, Jaroslav Halák, the Islanders' starting goaltender, suffered a lower-body injury sidelining him six weeks, leaving Greiss as the team's temporary starter.

On 12 July 2023, as a free agent from the Blues and despite contract offers, Greiss announced his retirement from the NHL and his professional ice hockey career.

[20] On September 25, 2024, Greiss announced his return to ice hockey by signing a short-term contract with Löwen Frankfurt, following the injuries of Juho Olkinuora and Cody Brenner.