A refrigerator comprising: a cabinet defining a storage space; a door configured to open and close the storage space and having an accommodation space; a viewing part passing through the door to communicate with the accommodation space; a door light configured to illuminate a rear space of the door; and a transparent panel assembly configured to cover the viewing part and being transparent or opaque so as to allow the viewing part to be selectively visible according to turn on/off of the door light, and an insulation member disposed along a circumference of the transparent panel assembly to thermally insulate a circumferential portion of the transparent panel assembly, wherein the transparent panel assembly comprises: a display configured to output a screen and being transparent; and a display light configured to emit light for so as to output the screen on the display, and a guide plate configured to diffuse light emitted from the display light, the guide plate being configured to illuminate the display from a rear side of the display when the display light is turned on, wherein the transparent panel assembly is configured to convert into a plurality of mode states, the plurality of mode states comprising: a transparent mode state in which the door light is turned on and the display light is turned off to allow the inner space of the refrigerator to be visible through the transparent panel assembly, an opaque mode state in which both the door light and the display light are turned off to make the inner space of the refrigerator invisible through the transparent panel assembly, and a screen output mode state in which the door light is turned off and the display light is turned on, the display being configured to operate and output screen through the transparent panel assembly. a display configured to output a screen and being transparent; and a display light configured to emit light for so as to output the screen on the display, and a guide plate configured to diffuse light emitted from the display light, the guide plate being configured to illuminate the display from a rear side of the display when the display light is turned on, wherein the transparent panel assembly is configured to convert into a plurality of mode states, the plurality of mode states comprising: a transparent mode state in which the door light is turned on and the display light is turned off to allow the inner space of the refrigerator to be visible through the transparent panel assembly, an opaque mode state in which both the door light and the display light are turned off to make the inner space of the refrigerator invisible through the transparent panel assembly, and a screen output mode state in which the door light is turned off and the display light is turned on, the display being configured to operate and output screen through the transparent panel assembly. a transparent mode state in which the door light is turned on and the display light is turned off to allow the inner space of the refrigerator to be visible through the transparent panel assembly, an opaque mode state in which both the door light and the display light are turned off to make the inner space of the refrigerator invisible through the transparent panel assembly, and a screen output mode state in which the door light is turned off and the display light is turned on, the display being configured to operate and output screen through the transparent panel assembly.