The prolific Scotland international has been named as one of two reserves for Tokyo along with Harry Martin.
Forsyth’s omission from the 16-man squad has been met with incredulity by many in the hockey world and will come as a huge blow to the player who was also overlooked for the Rio Games in 2016.
The 29-year-old, who plays for Surbiton, has regularly topped the scoring charts in English club hockey.
Calum Giles, who played for GB at the 1996 and 2000 Olympics, tweeted: “Have to say I’m more than a little shocked at the omission of Alan Forsyth from the GB Hockey team. Seems the opinion of the majority of the hockey population. Proven goalscorer at the highest level.”
Others on Twitter were less diplomatic, with Forsyth’s exclusion branded “a shocking decision” and “an absolute disgrace”.
In a statement, Scottish Hockey said Olympic selection was the sole preserve of the GB set-up.
“Scottish Hockey is invested in the development of all our performance athletes, and having Scottish athletes represent Great Britain at the Olympic Games is extremely important to us,” said the statement.
“Therefore, we are delighted when one of our athletes is selected, and disappointed when any of our athletes are not selected for the Olympic Games - the premier event in world hockey.
“Within the GB partnership, as a matter of course for all Scottish athletes, selected or otherwise, we request and receive feedback on the rationale leading to selection decisions.
“We know that selection in team sport is complex and multi-faceted, and as detailed in the GB Framework Agreement, the GB performance director, GB head coach and assistant coaches form a panel and have unambiguous accountability for the selection or de-selection of athletes for all GB related tournaments.
“Scottish Hockey is committed to the GB Framework Agreement, and as part of the planned cyclical process, we will use the opportunity to feedback on the effectiveness of the framework from a Scottish perspective, within the wider GB context.
“We look forward to getting behind the Scottish, English and Welsh athletes competing in GB teams in the Olympics.”
Scotland midfielder Sarah Robertson has been named in the women’s Olympic squad, with compatriot Amy Costello a reserve.