Robert Dwayne Gruss (born June 25, 1955) is an American prelate of the Roman Catholic Church.

[1] After deciding to enter the priesthood, Gruss enrolled at St. Ambrose University in Davenport, Iowa, where he earned a Bachelor of Theology degree in 1990.

[2][4] After his 1994 ordination, the diocese assigned Gruss as parochial vicar of St. Paul the Apostle Parish in Davenport, Iowa.

He served the same role for three parishes in central Iowa from 1997 to 1998; Bishop William Franklin appointed Gruss as vocations director in 2004 and chancellor in 2005.

His episcopal consecration took place on July 28, 2011, at the Rushmore Plaza Civic Center in Rapid City, South Dakota.