Vice president of marketing for Visit Indy Chris Gahl says 12 conventions cited RFRA as the reason they opted out of holding their meetings in Indiana.
The number of Indiana students receiving vouchers increased by almost half during the 2014-2015 school year.
The Center for Education Reform ranked Indiana's voucher program as the best in the country.
A proposal to let voucher-accepting private schools opt out of the state's ISTEP+ test fizzled in committee Wednesday.
Voucher proponents say Indiana's maximum award amount is too low to continue attracting new students at the current pace.
D or F rated private schools had, on average, twice as many voucher-recipient students as the A schools.
Indiana awarded 19,809 private school tuition vouchers for the 2013-14 school year, up from 9,139 last year and 3,911 two years ago.
Roughly 40,000 low-income 4-year-olds would qualify for preschool vouchers each year under the measure Gov. Mike Pence is proposing.
The law increases the maximum amount of a voucher, and guarantees eligibility to siblings of voucher students.
But the expansion isn’t nearly as broad as many, including Pence, wanted.