He is ahead of US President-elect Donald Trump in the readers’ online vote for this year’s award.
The two were neck and neck at 9% each earlier this week but Mr Assange now has 12%, compared with 11% for Mr Trump.
Time selects the person who has, for better or worse, made the greatest impact on the world in the past year.
The magazine’s editors make the final selection but the poll is a way for readers to voice their opinions.
Voting ends on December 4.
Mr Assange has been living in the Ecuadorian embassy in London for more than four years and has been granted political asylum by Ecuador.
He faces a sex allegation in Sweden, which he has always denied but believes that if he leaves the embassy he will be extradited to the US for questioning over the activities of WikiLeaks.
Mr Assange was interviewed inside the embassy last week in the presence of prosecutors from Sweden.
The Swedish Prosecution Authority said it would take a view on the continuation of its investigation.
Mr Assange’s lawyer, Jennifer Robinson, said he had co-operated fully with the interview and hoped the Swedish prosecutor would give “impartial and objective” consideration so the matter could be closed.