Cook tweeted today that he is calling on Arkansas Governor Asa Hutchinson to veto a similar bill in his state.
Supporters of the Indiana law say it prevents the government from compelling people to provide services such as wedding photography for same-sex weddings or other activities they find objectionable on religious grounds.
"This bill is not about discrimination," Pence had said, "and if I thought it legalized discrimination I would have vetoed it."
Salesforce.com, which bought ExactTarget in Indiana in 2013, is asking other tech companies to respond to Indiana's law. Salesforce.com CEO Marc Benioff was among the CEOs who signed a letter to Gov. Pence on Wednesday.
"We firmly believe in the separation of church and state as provisioned in the First Amendment to the Constitution of the United States. The [Religious Freedom Restoration Act] clearly blurs that line and opens the door to blatant discrimination," Benioff and other CEOs wrote in the letter.
On Thursday, he tweeted that his company, based in San Francisco, is "canceling all programs that require our customers/employees to travel to Indiana to face discrimination."
"I hope that in the future the legislatures in the nineteen states that have these laws on the books will reconsider their actions," Stoppelman wrote in an open letter to "states considering imposing discrimination laws." "In the meantime, Yelp will make every effort to expand its corporate presence only in states that do not have these laws allowing for discrimination on the books."