HONG KONG — Joshua Wong, a prominent democracy activist from Hong Kong, was denied entry into Malaysia on Tuesday in what critics called an act of political censorship by the Malaysian government.

Mr. Wong was scheduled to speak at forums hosted by Malaysian youth activist groups in cities across the country from Tuesday to Friday. He said Malaysian immigration officers at Penang International Airport on Tuesday had told him that a “government order” barred him from entering the country.

In a statement Tuesday evening, Mr. Wong, 18, said he was prepared to speak on democracy in China and to share with the Malaysian audience his experience during the Umbrella Movement, a large, student-led protest in Hong Kong last year demanding a free election of the city’s leader.

Eric Paulsen, co-founder of the Malaysian civil rights group Lawyers for Liberty, said that the Malaysian government was trying to contain the influence Mr. Wong might have had on the country’s young people, who, dissatisfied with a rising cost of living and rampant corruption, have been increasingly active in street protests since the beginning of the year.