The forum is being sponsored by Reno Public Radio, KNPB-TV, and the Reno Gazette-Journal.
Sponsors say Republican Mark Amodei, Democrat Kate Marshall, Independent American Party member Tim Fasano, and independent Helmuth Lehman have confirmed their attendance.
The hour-long debate begins at 6 p.m. and will take place at KNPB Channel 5. The TV station will broadcast the first half-hour live.
KUNR-FM will air the full hour, and station manager Brandon Rittiman says the entire debate will be steam online.
The Sept. 13 special election will fill a vacancy created after Republican Dean Heller left the House in May to fill a Senate vacancy.