The impact of smaller firm size on corporate social responsibility (CSR) is ambiguous. Some contend that small businesses are socially responsible by nature, while others argue that a smaller firm size imposes barriers on small firms that constrain their ability to take responsible action. This paper critically analyses recent theoretical and empirical contributions on the size-social responsibility relationship among small businesses. More specifically, it reviews the impact of firm size on four antecedents of business behaviour: issue characteristics, personal characteristics, organizational characteristics and context characteristics. It concludes that the small business context does impose barriers on social responsibility taking, but that the impact of the smaller firm size on social responsibility should be nuanced depending on a number of conditions. From a critical analysis of these conditions, opportunities for small businesses and their constituents to overcome the constraining barriers are suggested.