Embodiments of a system are disclosed for stress assessment of a call center agent while interacting with a customer. The system is for use with a communication network. The system includes a stress assessment device and an agent device that includes an imaging unit. The agent device is configured to capture video of a target region of exposed skin of the agent using the imaging unit, collect customer interaction data based on interaction with a customer device over the communication network, and communicate the captured video and the customer interaction data to the stress assessment device. The stress assessment device is configured to passively estimate agent stress-level based on the received video, and generate feedback to the agent based on correlation between the customer interaction data and the estimated stress-level over a predefined time interval.