Nat Fraser and Malcolm Webster lost appeals against their convictions this year for killing their wives.
Fraser, 54, has twice been found guilty of organising the murder of Arlene Fraser in 1998. He lost an appeal in October this year.
Webster, 54, was jailed for a minimum of 30 years for killing his then-wife Claire Morris, 32, in a staged car crash in Aberdeenshire in 1994 and attempting to kill Felicity Drumm in New Zealand in 1999 to claim insurance money. Earlier this month, judges at the Court of Criminal Appeal in Edinburgh rejected a claim that he was the victim of a miscarriage of justice.
Figures reveal Fraser received £822,882.06 in legal aid while Webster's bill was £386,668.33.
Ms Morris's brother Peter said: "What I would like to see is better balance in the shape of the amount of money spent on victims compared to the amount spent on the criminals."
A spokeswoman for the Scottish Government said: "Legal aid applications are subject to statutory tests that are applied on an individual basis.
"The Scottish Legal Aid Board applies these tests and the Scottish Government is prohibited from seeking to influence or interfere with any application."