In Wednesday's Court of Cassation ruling, judges "established new parameters" for the calculation of alimony, the court's chief press officer Raffaele Botta said in a statement.
While alimony payments had previously been established with the goal of "maintaining the matrimonial standard of living", the court instead said on Wednesday that payments should be based purely on guaranteeing "the economic independence or self-sufficiency of the spouse who requests it".
In other words, divorcees are likely to receive smaller monthly payments than in the past, particularly in cases where their ex-spouse was wealthy.
The president of the Italian Academy of Family Lawyers, Gian Ettore Gassani, said the ruling, which related to the divorce between a former Italian minister and his ex-wife, was a "revolution".
"One of the fundamental principles of the law governing alimony has been cancelled," said Gassani.
The court itself said that the change was necessary in order to "overcome the patrimonial view of marriage as 'final settlement'.
Modern marriage, the judges said, was generally an "act of freedom and personal responsibility", and so should be completely "dissolvable", meaning that ex-spouses were not responsible for a partner's possible loss of income during the marriage.
Italy's alimony laws have led to controversial decisions over the years.
In 2013, a woman was denied financial support from her ex-husband due to a "shopping addiction", while last year, a court in Padua ruled that a man could make his monthly maintenance payments to his wife in the form of pizza.
Divorce, Italian style
Italy had no provision for divorce until 1970 and the difficulties caused by this were the subject of a celebrated 1961 film "Divorce, Italian Style". The comedy features Marcello Mastroianni as a Sicilian noble who cooks up a plot to kill his wife in a crime of passion so he can be free to marry a younger model.
However, legislation which came into force last year made it easier and quicker to end marriages - prompting a 57 percent surge in the divorce rate.
Now only one year of official separation is necessary before couples can begin divorce proceedings, or six months in the case of a separation by mutual consent. Previously, couples had to be officially separated for three years.