Nathan Frederick Cayless (born 28 March 1978) is an Australian former professional rugby league footballer who played in the 1990s, 2000s and 2010s, and has coached in the 2010s.

In the 1998 NRL season, Cayless made 19 appearances as Parramatta reached the preliminary final but were defeated 32-20 by rivals Canterbury-Bankstown in extra-time after leading the game 18–2 with less than 10 minutes to play.

The following year, Cayless played in the club's 18–16 loss against eventual premiers Melbourne in the preliminary final after leading 16–0 at half time.

In the 2001 NRL season, Cayless captained the Parramatta side to the Minor Premiership where they set numerous records throughout the year.

[5] In the 2005 NRL season, Cayless captained Parramatta to their second minor premiership in five years and were favorites along with St. George to take out the title but suffered a 29–0 loss to North Queensland in the preliminary final at Telstra Stadium.

Parramatta lost the final 23–16 at Telstra Stadium but Melbourne's premiership win was stripped the following year due to multiple and deliberate breaches of the salary cap.