Chuck Thornton, deputy director of the American Civil Liberties Union of Oklahoma, described the measure as an "ugly piece of legislation that was used to inflame passions against the Islamic community."
Thornton also was concerned that the measure would send the wrong message to international investors.
"I think when members of the international community look at something like this, it may give them reason to pause if they are considering investing in Oklahoma," Thornton said.
The state has faced an increasing number of lawsuits challenging state statutes during recent years.
Fifteen cases were filed in 2007, followed by 18 in 2008 and 24 in 2009. The attorney general's office handles most cases, but sometimes the state hires outside counsel. An estimate of the number of hours spent on those cases was not available Wednesday. In one example, a lawyer billed the state $90,000 to defend against two lawsuits that challenged abortion laws. Both laws were eventually overturned.