Various technologies described herein pertain to using detected physical gestures to cause calls to transfer between client devices. A physical gesture between a first client device and a second client device can be detected (e.g., utilizing the first client device, the second client device, a disparate client-side device, a server, etc.). The first client device participates in a call, while the second client device is not participating in the call at a time of the detection of the physical gesture. Responsive to detection of the physical gesture, participation of the second client device in the call can be initiated. Participation of the second client device in the call can be initiated by causing the call to transfer from the first client device to the second client device or causing the second client device to join the call while the first client device continues to participate in the call.