In the years leading up to World War II, Prince Albert, Duke of York, struggles with a severe stammer that undermines his public speaking abilities and erodes his confidence. His wife, Elizabeth, is determined to find a remedy for her husband's affliction, leading her to Lionel Logue, an unorthodox Australian speech therapist. Despite an initial clash of personalities and methods, the Duke reluctantly agrees to undergo treatment. Logue insists on referring to the Duke by his family name, Bertie, a breach of royal protocol which serves to establish a sense of equality between therapist and royal patient.

As political tensions escalate in Europe and his older brother King Edward VIII's reign is threatened by scandal and abdication, Bertie faces the increasing likelihood that he will have to assume the throne. His speech impediment poses a significant hurdle as the role demands public speaking. With Logue's unconventional technique and persistent coaching, a deep bond of trust and friendship develops between the two men. This alliance becomes the cornerstone in Bertie's personal battle to overcome his stammer and find his voice as a leader of his people.