During the last couple of years, it has become more and more normal for brands to utilise influencer marketing on the social media platform Instagram. Simultaneously, the world has experienced a rise in sustainable consumerism. However, only little research has been focused on the combination of influencer marketing and sustainability, which is why this thesis has investigated this particular aspect. More specifically, this study has explored influencer credibility and its influence on consumers’ attitudes and beliefs in regard to sustainable purchasing intention. This has been studied through a case study focused on young UK consumers. Hence, the aim of this thesis has been to investigate how the perceived credibility of UK influencers on Instagram influences young UK consumers’ beliefs and attitudes in relation to purchasing advertised sustainable products.

In order to gain an insight into how young UK consumers’ attitudes and beliefs toward sustainable promotions are influenced by influencers’ perceived credibility, we utilised two theoretical approaches. First, we needed an understanding of source credibility, where we drew on Ohanian’s (1990) three credibility attributes of trustworthiness, expertise, and attractiveness. Second, Fishbein and Ajzen’s Reasoned Action Approach (2010) provided us with a deeper understanding of how individuals form purchasing intentions and reach purchasing behaviour based on behavioural, normative, and control beliefs.

To answer our research question, we conducted qualitative semi-structured interviews with five UK citizens in the ages 19-29 years old, who all followed one or numerous UK influencers who had promoted sustainable products on Instagram. To manage our data retrieved from the interviews, Nigel King’s Template Analysis was used, which allowed us to create themes and gather an overview of the vast amount of data. We created themes and codes mainly deductively based on the theoretical framework and structured the analysis based on the themes. This provided us with an in-depth understanding of the various aspects that influence the interviewees’ attitudes and beliefs in terms of sustainable purchasing intention and behaviour. Finally, the analysis was completed with a synthesis, gathering significant findings from the different themes in order to understand how credibility had influenced the different interviewees’ attitudes and behaviours.

Based on the analysis, it was found that the attribute of trustworthiness was the most important credibility attribute for the interviewees in regard to sustainable purchasing behaviour. The attributes of expertise and attractiveness were found to be able to enhance and support influencers’ perceived trustworthiness, making influencers more credible. The analysis demonstrated that perceived credibility could influence behavioural beliefs and control beliefs, though it was not found that perceived credibility could directly influence normative beliefs. Interestingly, the study has discovered aspects that influence perceived credibility, namely background factors, attitudes, and normative beliefs.

Hence, it can be concluded that the perceived credibility of UK influencers has been able to influence the interviewees’ attitudes and beliefs concerning purchasing sustainable products promoted by influencers on Instagram. This is mainly done through the attribute of trustworthiness which can influence the interviewees’ behavioural and control beliefs.