The recently published guidelines for the medium term development of Latvia’s tax system (Nodokļu un nodevu sistēmas attīstības pamatnostādnes 2011-2015” have for the first time introduced social fairness (socialais taisnīgums) as an explicit goal of Latvian tax policy. Social fairness is further explained in the guidelines as “a more progressive tax system” and a “lower tax burden on lower wage workers and a higher tax burden on exclusive properties”. The challenge for policy-makers is how to realise this goal in combination with the other goals, in particular the goal of improving the competitiveness of the Latvian economy. The aim of this paper is to operationalise the concept of fairness of a tax system by developing quantitative indicators of tax fairness.