Vulnerable consumers are likely to fall victim to negative marketplace outcomes due to the secondary effects of marketing practices. In particular, credit card targeting directed towards young people elicits ethical criticisms because of the perceived vulnerability of the target segment, the targeting efforts that are deemed more predatory than informative, and the stigmatising protectionist policies that limit the youths' financial freedom. Vulnerable consumers are often overlooked in marketing considerations, leaving it to the public policy to intervene. This thesis aims to show that vulnerability is a marketing problem as much as it is a public policy issue, by highlighting the social effects of unethical marketing directed towards vulnerable consumers. The study depicts how young people, supposedly representing the most educated segment of the population, come to experience vulnerability due to credit card misuse and indebtedness. In addition, the study introduces a new concept and measure of susceptibility to credit card misuse and indebtedness (SCCMI) to investigate the extent to which youths are influenced by credit card temptations, which affect their likelihood to experience negative credit card outcomes. This study examines youth vulnerability and susceptibility to credit card misuse and indebtedness in a cross-country context, as the issue of vulnerability and power imbalance is arguably more pressing in the international market. The sampling involves young (18-25 years) credit card users in Singapore, Malaysia and the UK. These countries represent different degrees of credit card issuance and consumer protection regulations, which affect the youths' credit card attitude and behaviour. The first study utilises qualitative methodology to examine youth vulnerability to credit card misuse. Baker et al.'s (2005) situational framework of actual consumer vulnerability helps to identify relevant themes pertained to the youths' experience of credit card misuse and indebtedness. The qualitative study also serves as an exploratory phase to the subsequent quantitative study. The qualitative results enhance the conceptualisation and measurement scale development of SCCMI measure. The study then tested the validity, reliability and parsimony of the SCCMI measure and its proposed antecedent and consequent factors across the Malaysian, Singaporean and UK country samples.Vulnerability and susceptibility assessments in this study yield theoretical, methodological and practical implications. Vulnerability analysis draws upon the internal characteristics and external conditions that both facilitate and impede such vulnerability. Meanwhile, assessment of susceptibility provides an analytical tool to foresee and pre-empt future vulnerability. This study offers methodological contributions in its use of mixed methods, as a qualitative inquiry aids in understanding vulnerability while quantitative inquiry focuses on foreseeing potential vulnerability. A cross-country study analysis is valuable as it sheds light on the differences and similarities of consumer vulnerability and susceptibility across developing and developed countries. The study inform marketers that there are negative social consequences arising from unethical targeting practices, which leads to distrust and scepticism over credit card marketing directed towards youths. However, the youths' experience of vulnerability also varies across individuals, which indicate that protectionist policies that shield the entire youth population from credit card exposure are not always necessary. Both credit card marketers and policy makers have the capacities to redress and pre-empt vulnerability without sacrificing the youths' financial welfare and rights to harness the benefits that credit cards have to offer.