Facebook members will find out from 17:00 BST whether they are among the 87 million potential users whose data was shared with Cambridge Analytica.
Every account holder will receive one of two notices informing them whether their data was breached.
The tech giant said people will also be shown what apps they use and what data those apps may have gathered.
Facebook has additionally suspended a data analytics firm called Cubeyou, ahead of an investigation.
The tech giant will look into whether Cubeyou collected data for academic purposes and then used it commercially, following a partnership with Cambridge University in the UK.
The investigation follows allegations reported by CNBC, regarding a personality quiz called “You Are What You Like,” also known as “Apply Magic Sauce”.
Cubeyou denies the allegations. Both the firm and Cambridge University state that the app made it clear that data was for use in both academic and business purposes, the BBC reported.