Posters against China clearing the path for President Xi Jinping to effectively remain in power for life have appeared in several Western universities, the media reported on Monday.
China's parliament, the National People's Congress, overwhelmingly passed the constitutional changes on Sunday.
The posters, written in Chinese and English, have featured phrases such as "not my president" and "I disagree".
They began appearing on some US university campuses last week, and were later reported in countries including the UK, France, the Netherlands, Australia and Canada.
A Twitter account @StopXiJinping has been posting links to the posters for download and encouraging others to join what it calls "our campaign".
A user operating the account told that it was being run by Chinese university students and graduates who were living abroad but wished to remain anonymous.
The person did not give further details.
"We spoke up as we genuinely believe that Chinese citizens, overseas or at home, have the right to express opinions free from fear," the account tweeted had tweeted before the move on March 9.
The Twitter campaign has advised students to put up posters only at night, and to wear face masks.