Diaries of Welsh ministers' meetings with external organisations are to be published from later this year.
Welsh Government said the details of ministerial diaries were being published to aid transparency.
The Tories said ministers were "dragged kicking and screaming" to the decision while Plaid Cymru called it a victory for campaigners for open government.
Campaign group Unlock Democracy said the information should be "meaningful" so decisions could be scrutinised.
Kirsty Williams, Liberal Democrat education secretary, is already publishing her ministerial diaries on her own website.
There have been longstanding calls for Welsh ministers to produce details of meetings with lobbyists.
A note on the Welsh Government's website said First Minister Carwyn Jones had agreed to publish details of meetings between ministers and representatives from external organisations.
The information will be published on the Welsh Government's website quarterly, the note said, with the first publication expected shortly after March.
The diaries will detail the name of the minister, the date and type of the meeting and the name of the organisation or individual met.
The UK government already publishes details of meetings with ministers.
Lobbyists are organisations or individuals who work to influence government. They may work for commercial bodies, charities or other organisations.
Campaigners have argued across the UK for greater transparency over how lobbyists interact with ministers to be scrutinised. Other parts of the UK currently operate lobbyist registers.
The assembly's standards committee is currently holding an inquiry into whether tougher regulations are needed in Wales, although the former standards' commissioner Gerard Elias said he had received no complaints around the issue.
Jane Hutt, the Welsh Government's business minister, has said ministers never meet commercial lobbyists.
Alexandra Runswick, of campaign group Unlock Democracy, welcomed the decision, but said the public needed access to "meaningful information" if publishing diaries was to be an "effective tool to scrutinise actions taken and policy decisions made behind closed doors".
"This is an important first step towards increasing ministerial accountability and creating greater transparency around policy decision-making," she said.
"However, we already know from diary publication measures in Westminster and Holyrood [the Scottish Parliament] that this move can create the illusion of transparency where in fact very little exists."
Diaries should include details of policies discussed, she said, adding the Welsh Government should commit to putting in place a register of lobbyists "to ensure that those seeking to influence the policy-making process can be held to account".
Plaid Cymru AM Neil McEvoy said: "This is a victory for all who are campaigning for open government in Wales. The public will finally be able to see who their government ministers meet."
A UKIP spokesman said: "This is of course standard practice with UK government ministers and we find it surprising it has taken so long for the Welsh Government to implement this."
A Conservative spokesman said First Minister Carwyn Jones had been "dragged kicking and screaming into this decision".
"For some time we have been pressing the Welsh Labour Government to be more open and transparent, and we are pleased - if a little disappointed - that it has taken so long," the spokesman said.
A Welsh Government spokeswoman said it "keeps under review information which can be proactively published",
She added: "The first minister considered it appropriate to release details of ministerial diaries in order to aid transparency."