Mohammed Zaher al-Shurqat was walking down a street in the southern Turkish city of Gaziantep close to the Syrian border when he was targeted by the gunman, the Dogan and Anatolia news agencies reported.
IS accused of kidnapping 300 Syrian factory workers
El-Shurqat worked for a channel called Aleppo Today TV which is strongly opposed to IS militants who have taken control of much of Syria's northern Aleppo province.
He was immediately hospitalised and is in intensive care, the Turkish reports said, without giving further details.
According to Ibrahim al-Idelbi, a Syrian activist in Gaziantep, this was the second attempt against Shurqat's life in three months.
Idelbi told AFP in Beirut that Shurqat was a rebel commander who had fought President Bashar al-Assad's troops and a media activist in his home town, Al-Bab, until IS took over. He became a journalist with Aleppo Today after he moved to Turkey.
Syrian civilians return to ravaged town retaken from Islamic State
Citing a friend who visited Shurqat in hospital in the southern Turkish city, Idelbi said he was "still alive".
Another activist, Assaad al-Achi, confirmed the report. "When Daesh took control he started a programme on Aleppo Today against Daesh," he said, speaking to AFP via the Internet in English and using an Arabic acronym for IS.
Turkish police have studied security camera footage and interviewed witnesses and believe the shooting was carried out by a member of IS, Dogan added in its report.
Several Syrian journalists who fled the country's five year civil war use Gaziantep as a base but it has become an increasingly dangerous location from which to report.
A Syrian activist who produced documentaries hostile to the Islamic State group, Naji Jerf, was shot dead in Gaziantep in December in a crime that caused international concern
At the end of October, IS claimed responsibility for killing young activist Ibrahim Abdelkader and his friend Fares Hamadi. They were found decapitated in a house in the city of Sanliurfa just east of Gaziantep.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ