O'Neill spent much of his playing career in Scotland and lives in Edinburgh
The Scottish FA have made an official approach to their Northern Ireland counterparts for permission to speak to Michael O'Neill.
O'Neill, 48, is the SFA's preferred candidate to succeed Gordon Strachan as Scotland manager.
Strachan left in October following Scotland's failure to reach the World Cup play-offs.
In an attempt to retain O'Neill as manager, the Irish Football Association has offered him an improved contract.
O'Neill has been in charge of Northern Ireland for six years but just missed out on World Cup qualification.
The former Brechin City and Shamrock Rovers boss is under contract until 2020, on a deal believed to be worth £500,000 a year.
O'Neill approach good fit for Scotland - NI analystO'Neill is preferred candidate for Scottish FA
O'Neill, who lives in Edinburgh, guided Northern Ireland to Euro 2016 - their first major finals since the 1986 World Cup.
He steered them to second place behind Germany in a World Cup qualifying group that included the Czech Republic and Norway only to lose out on a place at Russia 2018 after a 1-0 aggregate loss to Switzerland in a play-off.
Northern Ireland are currently 23rd in the Fifa rankings, six places above Scotland.
Scotland have not been to a major tournament since the 1998 World Cup.
Under Strachan, Scotland were unbeaten in their final six qualifying matches but finished third behind group winners England and Slovakia.
O'Neill is the manager the Scottish FA want to replace Strachan (left)Michael O'Neill factfileBorn 5 July 1969Began career with Coleraine in Irish League, before joining Newcastle UnitedPlayed as a midfielder and forward during a 20-year playing careerAmong the clubs he played for were Dundee United, Hibernian, Coventry City, Wigan Athletic and St JohnstoneMade 31 appearances for Northern Ireland, scoring four goalsWas in charge of Brechin City and Shamrock Rovers before being appointed Northern Ireland boss in December 2011
Source: bbc.com