Criminal victims will in future be given an explanation by the Crown Office if it decides not to pursue a criminal prosecution.
Colin Boyd hopes the new policy will improve the Crown's image
Lord Advocate Colin Boyd claimed the move will help combat the "secretive" perception of the legal system.
Reasons will be given every time a decision is taken not to proceed, drop or accept a plea in a case.
They will not be given where a public interest has to be protected or where confidential information is involved.
Under the new system, victims of crime and their next-of-kin, where a fatality is involved, will now routinely be able to request and receive from the prosecution an explanation for the decision not to proceed.
Mr Boyd said the Crown previously did not give reasons for decisions but this had started to change in recent years.
He said: "We have been giving reasons for decisions in child abuse cases and to many other victims of sexual crimes.
"But for many others it has been a source of grievance against the department which has been seen as closed and secretive.
"I do not believe this rule should be maintained in a modern prosecution service.
"If we are confident of the quality of our decision-making, we should be prepared to be open and accountable to those whose lives have been affected.
"I hope this new policy will give greater confidence to the victims of crime and to the wider public in the work of our prosecution service."
Scotland's top prosecutor made the announcement during a parliamentary debate on the modernisation of the Crown Office and Procurator Fiscal Service on Thursday.
Pauline McNeill, convenor of Holyrood's justice 1 committee, praised the Lord Advocate and his colleagues for their forward-thinking.
She said: "I think it is a mark of the current thinking of our law officers that they are responding to the demand of our constituents and the general public."
Liberal Democrat justice spokesman Jeremy Purvis joined in the praise and said: "I warmly welcome the comments of the Lord Advocate in response to requests from individuals to understand exactly the process, especially when decisions of no further action are taken."
Scottish National Party justice spokesman Kenny MacAskill backed the reforms and said that in the past the Crown Office had "failed to address the needs" of the people with whom it came into contact.
He said: "It was to some extent a legal sausage-making machine, it was a process that went through without any understanding that there were individuals who had emotions and perhaps most importantly had rights."
He also urged ministers and Mr Boyd to consider introducing evening and weekend sheriff court sittings to deal with motoring offences and breach of the peace.
Tory justice spokeswoman Annabel Goldie welcomed the move but attacked the government for the underlying problems of the Scottish justice system.
She said: "The sad reality is that under this executive, with its lack of clarity of vision, its lack of resolve and its lack of leadership, Scotland's criminal justice system is in turmoil and that is not the fault of the Lord Advocate."
During the debate Mr Boyd also described how the Proceeds of Crime Act had become a "powerful tool" in the fight against crime by helping to target criminal assets.
He told the parliament that almost £3m of criminal assets had been seized since its introduction.
He said: "We are, without doubt, leading the UK in this area. We were the first department in the UK to be granted either a cash seizure or a civil recovery order."