In a report published on Wednesday, the organisation warned that the murders of journalists and activists around the world, compounded by surveillance and restriction of online spaces, was having a chilling effect on freedom of opinion and expression.
It noted that "technology has given us more opportunities to speak and to know than any known period of human endeavour, yet globally free speech is declining".
Article 19 takes its name from an article in the Universal Declaration of Human Rights which calls for the rights of freedom and expression.
The organisation reported that 78 journalists and 312 activists were murdered in 2017, while another 326 were imprisoned. More than half of those imprisoned were in Turkey.
This is driving self-censorship among journalists, which the organisation claimed was the largest contributor to the suppression of free speech.
This year, the killing of Washington Post columnist Jamal Khashoggi in the Saudi consulate in Istanbul drew widespread attention and criticism of the Saudi government.
That criticism was not echoed by Donald Trump, however, who himself has consistently criticised the media - something which the publisher of The New York Times claimed was "putting lives at risk" following the shooting of five newspaper staff in Maryland.
Meanwhile in countries such as Iran, Russia, and China, technological innovations to block and filter internet communications have received heavy investments from the state.
After a decade of investment in an infrastructure project in Iran called the National Information Network (NIN), the government has successfully separated domestic and international internet traffic.
On the eve of 2018 and amid protests against the clerical regime, the regime revealed its ability to restrict the people of Iran to internet content approved by the state.
Moscow and Beijing have similarly been consistently tightening their control over citizens' use of the internet, including by prohibiting the use of privacy technologies.
Meanwhile in Cameroon and Ethiopia, regimes have targeted public protests by implementing total shutdowns of the internet.
The report claims that social media sites in the UK are facing potential curbs to free expression by poorly implemented measures targeting "dangers like cyber-bullying, trolling and under-age access to porn" as described by the government's plans for an internet safety strategy.
"Online communicators are increasingly penalised, with prison sentences handed out worldwide on the basis of Facebook posts, shares, and messenger group administration activities," states the report.
"Similar trends have occurred relating to video services: as live streaming gained popularity in the last year, incorporated into platforms like Facebook and Snapchat, governments have attempted to restrict it, particularly during political protests, by blocking applications."
In its election manifesto, the Conservative Party said it would introduce a sanctions regime for companies that fail to meet their legal duties in regards to content that is deemed in breach of law.
The difficulties in establishing whether content could be illegal or not were highlighted earlier this year when YouTube deleted an archive of video evidence of potential war crimes in Syria.