The Supreme Court, in a statement, said it had granted Lopez the "humanitarian measures" for health reasons and "serious signs of irregularities" in the handling of the case that it did not specify.
Outside Lopez's house in the capital, Caracas, a few dozen supporters arrived carrying Venezuelan flags to celebrate along with journalists looking for information about whether the transfer may have been part of a larger deal between the opposition and President Nicolas Maduro's government.
The opposition has been demanding the release of dozens of activists it consider political prisoners, the most prominent being Lopez, in order to initiate talks aimed at resolving a political crisis that has left more than 90 people dead and hundreds injured.
"We spoke for like 40 minutes. He's hugging his children, he's with his wife. .... I'm sure they are celebrating," Lopez's father, who shares his son's name, said from exile in Spain. He said in recent days Lopez had been isolated in his prison cell without food and attributed his son's transfer to the considerable international pressure on Maduro's government.