She contended that votes for Democratic nominee Hillary Clinton driven by "fear" of electing Republican nominee Trump effectively "silence" nonmajor parties. Stein argued against "voting against someone," despite the concerns she has about Trump as president.
"It's important to remember the American people are actually clamoring for more choices and are unhappy with the Democratic and Republican nominees," Stein told CNBC's "Power Lunch," highlighting her opposition to trade deals and support of tougher regulations on Wall Street.
Stein currently receives just more than 3 percent of support in an average of national polls including her, Clinton, Trump and Libertarian nominee Gary Johnson, according to RealClearPolitics. Clinton, Trump and Johnson get about 42, 38 and 7 percent, respectively.
With Clinton and Trump getting high unfavorable ratings from voters, many have sought options beyond the major parties. Stein has looked to court disillusioned supporters of Sen. Bernie Sanders, who lost to Clinton in the Democratic primary.
"People aren't happy with this rigged economy or this rigged political system," Stein said.
Clinton got a bounce over Trump in polling since the Democratic National Convention. But in a tight race, votes for Stein or Johnson could tip the balance between the two major party candidates.