Philippe Van Parijs ascribes to a conception of justice that he terms real-libertarianism. Real-libertarianism holds that social justice should be properly understood as a situation where, subject to equal formal rights for all being respected, opportunities are distributed so as to maximize everyone’s real freedom, i.e. their effective capacity to turn material means into opportunities and to utilize these opportunities in accordance with their own conception of the good. In order for relevant equality in the capacity to turn means into opportunities to obtain, no-one person should be universally viewed as absolutely disadvantaged in comparison to others with regard to this capacity. Subject to the satisfaction of this criterion, termed “undominated diversity”, the direct institutional implications of ascribing to the real-libertarian conception of justice is, according to Van Parijs, that we should implement a basic income payment to all of society’s members at the highest sustainable level. The justification given for the payment of the basic income is that it will supply the people with the least opportunity with as much opportunity as they can possibly have. This thesis critically examines the connection between this real-libertarian conception of justice and Van Parijs’ specified proposal for a basic income. It argues that the basic income cannot be justified by simple reference to the real-libertarian criterion of distributive justice, called “leximin opportunity”. Rather, it is shown that Van Parijs’ normative case for a basic income rests on his application of conditions of envy-freeness and the liberal neutrality postulate. Further, it is argued that Van Parijs has not convincingly shown that the effective implementation of a basic income will operate in accordance with said conditions, and hence that his real-libertarian case for a basic income is weakened. The discussion leading to these preliminary conclusions is focused on the question of whether or not Van Parijs has been successful in showing that the basic income he prescribes will remedy inequalities that must be regarded as unjust on the real-libertarian view. From a purely theoretical standpoint, it concludes that there is a high probability for, and therefore reason to believe, that the answer to this question will be negative.