Winfried Conradi, a quirky music teacher from Aachen with a knack for bizarre pranks and a variety of alter egos, finds himself grappling with the loss of his beloved dog. Seeking to reconnect with his busy daughter, Ines, who is engrossed in her career as a business consultant in Bucharest, Romania, he takes a spontaneous trip to the city. Ines is buried under work as she tackles an outsourcing project in the oil industry, leaving little room for family connections.
Upon arriving, Winfried patiently waits for Ines in the lobby of a corporate building. After a long wait, Ines finally emerges with several board members in tow, heading to their next meeting. In a playful spirit, Winfried dons sunglasses and fake teeth, acting out a comical disguise. However, Ines appears oblivious to her father's antics, only briefly acknowledging him after work when she invites him to a prestigious business reception at the U.S. Embassy.
The reception is an eventful affair where they encounter Henneberg, a German CEO who Ines hopes to impress to secure a consulting contract. Although Ines tries to engage him, Henneberg seems much more captivated by Winfried, leading to an awkward evening where Winfried jokingly claims to have a "replacement daughter" due to Ines’s perpetual busyness. To Ines's dismay, Henneberg drops his focus on her in favor of joining Winfried for drinks, further complicating their already strained relationship.
As the days progress, Ines, overwhelmed by work pressures, struggles to maintain her composure. Missing a significant meeting due to oversleeping, she lashes out at Winfried, and feeling unwanted, he takes a taxi to the airport. Life continues for Ines, and one evening, while out with friends, she unexpectedly bumps into "Toni Erdmann" – a character played by Winfried in a wig and fake teeth. Ines plays along, although her irritation with her father's antics grows.
Winfried, as "Erdmann," randomly appears in her life at professional gatherings, party events, and even a Romanian family's Easter celebration, where he tricks her into performing Whitney Houston's "Greatest Love of All." This unusual bonding method, initially unwelcome, gradually softens Ines's stern attitude towards her father. She begins to see the value in his quirky methods and even integrates him into her work life.
As Ines prepares for her birthday brunch, the tension escalates into comedic chaos. Struggling with her outfit, she answers the door in nothing but her underwear as guests arrive, declaring the party a "naked party," provoking varied reactions from her friends. Winfried makes a grand entrance in a full-body Bulgarian kukeri costume, initially shocking before bringing laughter into the room. Their heartfelt hug outside in the park signifies a burgeoning reconnection, even as Winfried seeks assistance to emerge from his cumbersome costume.
Months later, Ines finds herself back in Germany for her grandmother's funeral, ready to transition to a new job in Singapore. Amidst a serene moment in the garden, she playfully grabs Winfried's fake teeth from his pocket and wears them, prompting Winfried to grab his camera for a photo, leaving her alone to reflect on the day's memories.
