Clinton will release her latest 2015 tax return, meaning she and her husband, former President Bill Clinton, will have released every year of their returns since 1977.
Kaine, on the other hand, will release the last 10 years of his own tax returns.
Trump, for his part, has refused to release his returns — something no major party presidential candidate has done since Richard Nixon.
Trump has said he is currently under audit and won't release the documents until the audit wraps.
But being under audit does not prevent anyone from releasing their returns. And Trump's refusal to make the documents public has led to questions from both sides of the aisle about what he may be hiding.
That includes Clinton's campaign, which released a web video Friday speculating what lies in the withheld tax returns.
The New York Times reported Thursday that Trump may not have paid any tax at all, despite claiming to be a billionaire. The Times report said Trump may have taken advantage of tax credits for developers that would bring his total taxable income to $0 — meaning he would pay less than middle-class and low-income families.
A tax return would also show how much money Trump makes a year. Trump has claimed to be worth $10 billion, but his annual income could be far less.
The returns would also show how much money Trump has donated to charity. Trump claims to donate to charitable organizations, but Washington Post reporter David Farenthold has found little evidence to support Trump's charitable donation claims.
Finally, a tax return could show what kind of financial ties Trump has to foreign countries — including Russia, which has seemingly sought to meddle in the 2016 election through a possible email hack of numerous Democratic campaign entities.
Those ties could be revealed, as Americans can claim tax credits for any money earned abroad.