Isaiah Greenhouse (born July 15, 1987) is a former American football linebacker and fullback.

He was signed by the Houston Texans as an undrafted free agent in 2010.

After going undrafted in the 2010 NFL draft, Greenhouse was signed by the Houston Texans on May 18, 2010.

He was cut on September 3, 2010, and signed to the practice squad two days later.

He was waived on September 3, 2011, and was signed to the practice squad the next day.