It’s understood the Lothians MSP has made the decision amid frustration over her party’s position on Brexit and Jeremy Corbyn’s failure to get behind a “People’s Vote.”
She will make an announcement on her departure in the coming weeks, according to the Sunday Times.
Former Labour leader Kezia Dugdale has refused to deny claims that she will quit Holyrood later this Summer.
A spokesman for Ms Dugdale refused comment on the claims today.
Ms Dugdale served as Labour leader in Scotland between 2015 and 2017, taking over from Jim Murphy. She revealed July 2017, while still labour leader, that she was in a relationship with the SNP MSP Jenny Gilruth.
Earlier this month she won a defamation case against the pro-independence blogger Winngs Over Scotland who sued over her claims that he was homophobic.
It’s also understood Dugdale has been unhappy at the direction of the party under Jeremy Corbyn and her successor Richard Leonard.
She prompted anger among some colleagues after standing down as leader when she agreed to appear on the reality TV show `I’m a Celebrity get Me out of Here’ while the Scottish Parliament was still sitting.
If she does quit there will be no requirement for a parliamentary by-election with the next person on Labour’s list automatically taking up the seat. Former MSP and minister Sarah Boyack, who is director of public affairs with the Scottish Federation of Housing Associations, is next on the list.