Ressa had pleaded not guilty in 2020.
The tax case is one of several government lawsuits that she and Rappler are facing, sparking press freedom concerns in the Southeast Asian country.
Ressa, the CEO and executive editor of Manila-based Rappler, received the Nobel Peace Prize for her work in 2021. The award also made her the first Filipino to win a Nobel Prize.
'Truth wins. Justice wins.'
Addressing reporters outside the court on Wednesday, Ressa said it was "emotional" for everybody, describing the charges as "politically motivated" in an attempt to stop journalists from doing their jobs.
"It took four years and two months," she said, in reference to the trial. "But today, facts win. Truth wins. Justice wins."
In a statement on the court decision, Rappler described it as "the triumph of facts over politics." The website thanked the court for "recognizing that the fraudulent, false and flimsy charges" were baseless.
The renowned journalist and her website still face three other criminal cases, most notably a cyber libel conviction that is now under appeal. If the conviction is upheld, Ressa could face nearly seven years in prison.
Why was Rappler accused of tax evasion?
Ressa founded Rappler to combat misinformation and document human rights abuses carried out by former Philippine President Rodrigo Duterte, including during his deadly war on drugs.
Her site, launched in 2012, is one of the most popular in the country. Philippines authorities ordered the website shut in June last year, affirming a 2018 order.
The order to shutter the website and the tax charges were based on accusing Rappler of violating a constitutional provision which bans foreign ownership and control of media companies in the Philippines.
The Securities and Exchange Commission accused Rappler of the violation after receiving funds from foreign investors including Omidyar Network and North Base Media.
However on Wednesday, the tax court ruled that the financial papers through which the funds were paid were non-taxable.
The legal fate of Rappler, however, remains unclear.
rmt/wd (AFP, Reuters)