Detention warrants were issued for 51 people over their alleged donations to a foundation that has been closed due to its ties to the Gulen movement.
State-run Anadolu news agency said Friday that police carried out operations in 6 provinces as part of an Istanbul-based investigation.
33 people from different occupations were rounded up while police were searching for the remaining 18 at the time of writing.
The suspects are accused of membership to the Gulen movement due to their alleged donations to a higher education foundation, named Türkiye Yüksek Tahsil Gençliği Öğrenim ve İhtisas Vakfı, which was closed down in the aftermath of the July 15, 2016 failed coup.
Turkish government accuses Gulen movement of masterminding the coup attempt while the latter denies involvement.
More than 150,000 people have been detained and over 77,000 have been remanded in prison over Gulen links since the failed coup.