A vehicular rear glass antenna system includes a rear window glass sheet, a defogger formed on a lower part of the glass sheet, and an antenna formed on an upper part of the glass sheet. This antenna includes (a) a feed point located at a position that becomes adjacent to a top or side member of a metal rear window frame of a vehicle body; (b) a horizontal strip that is connected to the feed point and becomes adjacent to the top member of the rear window frame; (c) a vertical strip downwardly extending from an end point of the horizontal strip; (d) a first return strip horizontally extending from a lower end of the vertical strip toward the feed point; and (e) a second return strip horizontally extending from a middle point of the vertical strip toward the feed point.