Apple is contributing $100,000 to fight Proposition 8, the California ballot measure that would define marriage as only between a man and a woman. The company’s announcement today came as the fight over Prop. 8 grows hotly contested, with recent polls showing the race tightening.

The Cupertino, Calif.-based company said in a statement:

Apple was among the first California companies to offer equal rights and benefits to our employees’ same-sex partners, and we strongly believe that a person’s fundamental rights– including the right to marry — should not be affected by their sexual orientation. Apple views this as a civil rights issue, rather than just a political issue, and is therefore speaking out publicly against Proposition 8.

Apple becomes the latest prominent Silicon Valley company to speak out against the measure. Google’s founders gave $140,000 to the “No on 8″ campaign — $100,000 from Sergey Brin and $40,000 from Larry Page, the San Jose Mercury News reported today. The Internet company, based in Mountain View, Calif., had earlier taken the unusual step of publicly opposing the measure, which would ban same-sex marriage, saying it would have a “chilling and discriminatory effect” on many of its employees.