Hundreds of delegates from across rural Scotland are converging on Stranraer to discuss issues affecting their areas.
The impact of Brexit and helping communities to "take action" are the key themes of the event.
The Scottish Rural Parliament is held every two years and is taking place in Dumfries and Galloway.
Emma Cooper, chief executive of Scottish Rural Action who organise the event, said it was an important time to speak with "one, powerful voice".
"Every community in Scotland will be affected by Brexit, with rural areas particularly exposed, so it's important that Scotland's rural communities organise and take action to prepare for the changes ahead," she said.
She said the programme would help people to take action in their communities and influence policy in a period of change.
"With the ongoing uncertainty over the Irish border arrangements it is fitting that we are meeting in Stranraer, a town that may yet be facing an EU border on its doorstep," she added.
The Scottish government sponsors Scottish Rural Action to build a rural movement and to organise a rural parliament event every two years.
Previous editions were in Oban in 2014 and Brechin in 2016.
Rural Affairs Minister Mairi Gougeon will open the event in Stranraer with Constitutional Relations Secretary Michael Russell bringing proceedings to a close on Friday.
"I am delighted to support Scotland's Rural Parliament - the only one in the UK - that provides an opportunity for rural communities to gather, share knowledge, and engage directly with policy makers on the areas that matter the most to them," said Ms Gougeon.
"I am particularly keen that young people contribute to that discussion, it is vital that they have a voice and that we work together for the benefit of our rural communities."
Why does it matter?
- Fiona Herron, campus manager at Dumfries and Galloway College's Stranraer campus, said: "We are looking forward to welcoming the Scottish Rural Parliament to Stranraer this week, letting people see what we do, and also learning from others, allowing us to make south west Scotland an even better place to live, work and study."
- Dumfries and Galloway Council leader Elaine Murray said the region was delighted to host the event. She added: "Our rural landscape often poses some unique challenges for our area and this is added to by the uncertainties of Brexit. Our rural economy is often heavily dependent on EU funding, particularly the Common Agricultural Policy, and the impact on our communities could be great if this funding is not replaced."
- Russel Griggs, who chairs the South of Scotland Economic Partnership, said: "I am sure the Rural Parliament will make a valuable contribution to ensuring the challenges we face are better understood, that the opportunities to secure a fairer and more inclusive economy for those in the south are secured and that our work in shaping the new agency is accelerated by the contributions of all those travelling to Stranraer."
- Peter Ross, who chairs Dumfries and Galloway's Leader Action Group, who are co-hosting the event said: "Rural Scotland must begin planning in earnest for a post-Brexit world, and the concerns of rural communities and organisations must be communicated to those with influence to shape post-Brexit policy. That is what this Rural Parliament is about and it's why this event is so critically important."