Willow Garage was a robotics research lab and technology incubator devoted to developing hardware and open source software for personal robotics applications. The company was best known for its open source software suite Robot Operating System (ROS), which rapidly become a common, standard tool among robotics researchers upon its initial release in 2010. It was begun in late 2006 by Scott Hassan, who had worked with Larry Page and Sergey Brin to develop the technology that became the Google Search engine. Steve Cousins was the president and CEO. Willow Garage was located in Menlo Park, California.

Robot Operating System is an open-source robotics middleware suite. Although ROS is not an operating system (OS) but a set of software frameworks for robot software development, it provides services designed for a heterogeneous computer cluster such as hardware abstraction, low-level device control, implementation of commonly used functionality, message-passing between processes, and package management. Running sets of ROS-based processes are represented in a graph architecture where processing takes place in nodes that may receive, post, and multiplex sensor data, control, state, planning, actuator, and other messages. Despite the importance of reactivity and low latency in robot control, ROS is not a real-time operating system (RTOS). However, it is possible to integrate ROS with real-time computing code. The lack of support for real-time systems has been addressed in the creation of ROS 2, a major revision of the ROS API which will take advantage of modern libraries and technologies for core ROS functions and add support for real-time code and embedded system hardware.