Definition
Game Theory Optimal (GTO) poker refers to a strategy based on the mathematics of game theory — specifically Nash Equilibrium — that is theoretically unexploitable. A player using a perfect GTO strategy cannot be beaten in the long run regardless of what their opponent does, because the strategy balances bluffs and value bets in precise ratios that deny opponents any profitable counter-strategy.
In practice, GTO play involves mixing different actions (bet, check, raise) with specific frequencies across your entire range of hands, making it impossible for opponents to know whether you hold a strong hand or a bluff. Solvers like PioSOLVER, GTO+, and MonkerSolver are used by professionals to calculate GTO strategies.
The term has become central to modern poker discourse, especially since the mid-2010s when solver technology became accessible. Players like Doug Polk, Phil Galfond, and Fedor Holz were among the first to popularize GTO thinking publicly.
Example
A GTO river strategy might involve betting with 60% of your strong hands and 30% of your bluffs, mixing in the exact frequencies that make you indifferent to your opponent's decisions.