Nguyen, also known by her blogging pseudonym, Me Nam -- which translates to "Mother Mushroom" -- was convicted of "conducting anti-State propaganda."
The 37-year-old, whose pseudonym originated with her nickname, "Mushroom," for her daughter, runs a blog which is frequently critical of the government, and covers issues such as land confiscation, freedom of speech and police brutality.
Nguyen also came to the attention of authorities in 2009 for her outspoken views against China's intervention in her country, including Beijing's financing of a controversial bauxite mine in the Central Highlands.
She was arrested by the Department of Public Security on October 10, 2016, according to the state-run Vietnam News Agency (VNA), which referred to her in reports as an "anti-state instigator."
She last posted on her Facebook page
on the date of her arrest.
The US called on Vietnam to release Nguyen and "all other prisoners of conscience immediately."
"We've seen some positive steps on human rights in Vietnam over the past few years. However, the trend of increased arrests and convictions of peaceful protests since early 2016 is deeply troubling," said State Department spokeswoman Heather Nauert.
Human rights and press freedom groups also condemned the trial and the sentencing.
"The Vietnamese government uses vague national security laws to silence activists and throttle free speech," said Phil Robertson, deputy Asia director at Human Rights Watch.
"International donors should not watch silently as activists like Nguyen Ngoc Nhu Quynh are jailed for a decade for defending the human rights of all Vietnamese."
She was the recipient of a Hellman/Hammett grant in 2010, which "recognizes courage in the face of political persecution," Human Rights Watch said.
Ahead of her conviction, PEN America released a statement calling for her "unconditional release
," while the Committee to Protect Journalists (CPJ) called the sentence an "obscene injustice."
"The harsh measures Vietnam has taken against journalists like Nguyen Ngnoc Nhu Quynh should be an embarrassment to the country's rulers," CPJ Asia Program Director Steven Butler was quoted as saying
"Quynh never should have spent a day behind bars. Condemning her to 10 years in prison for her writing is an obscene injustice."
Nguyen was arrested and imprisoned for 10 days in 2009, for "abuse of democratic freedoms and infringing on the national benefit," she told CNN in 2010
As a condition of her release, she agreed to give up blogging, posting a handwritten letter on her site in which she explained that she loved her country, but that the government felt this was the wrong way to express herself. After being denied a passport two months later, she decided to blog again.
"I write another entry on my blog, that I gave up already, but they didn't leave me alone," she said. "I have to take the right to say what I think."