This is the gr-qtgui package. It contains various QT-based graphical user interface blocks that add graphical sinks to a GNU Radio flowgraph. The Python namespaces is in gnuradio.qtgui, which would be normally imported as: from gnuradio import qtgui See the Doxygen documentation for details about the blocks available in this package. A quick listing of the details can be found in Python after importing by using: help(qtgui)