Publishing official letters sent to the governments of Albania, Bulgaria, France, Hungary, Italy, Serbia and Sweden, Muiznieks said there had been numerous instances in those countries of Roma settlers being forcibly evicted from their camps, often without consultation and "at very short notice."
"This situation increases the vulnerability of Roma families, prevents their social inclusion and impedes any prospect of regular schooling for their children," the commissioner said.
"EU member states have to abide by their human rights obligations by stopping such measures and investing more in finding durable housing solutions for Roma families."
Roma constitute Europe's largest ethnic minority. The European Commission estimates that of the 10 to 12 million Roma in the whole of Europe, some six million live in the EU, most of them EU citizens. However, they often remain victims of prejudice and social exclusion.
"Many Roma continue to face serious forms of discrimination and human rights violations by authorities at both national and local levels," Muiznieks continued, "in particular, forced evictions without due process and provision of adequate alternative housing continue unabated across Europe, in violation of member states' international human rights obligations."
Among the incidents Muiznieks highlighted was the reported eviction of about 200 people, mostly Roma from Romania and Bulgaria, from a site in the Swedish city of Malmo in November 2015.
In a separate letter to Italian Prime Minister Matteo Renzi, Muiznieks said he was "particularly troubled" by reports of more than 60 forced evictions last year in Rome.
In July last year, Muiznieks publicly stated that it was "time to debunk myths and prejudices about Roma migrants in Europe."
"It is time that politicians and media stop playing on fears of massive inflows of migrants and stigmatizing Roma in this context," he said at the time. "They should instead use objective demographic and economic data. Racist rhetoric should be firmly condemned at the highest level."