**Hypothesis 1 (H1).** *Environmental knowledge has a positive effect on sustainable consumption behavioural intention.*

Materialism has been extensively studied. Previous studies have reported numerous findings on the outcomes of materialism. Thus, for instance, Liu et al. (2022) found that materialism was positively associated with self-interest-triggered moral flexibility, and materialists judged immoral acts performed by the self and others more differentially. The marketing literature has previously reported numerous findings supporting a relationship between materialism and consumer–brand relationship outcomes (Fazli-Salehi et al. 2021). For instance, Le (2020) established that materialistic consumers were likely to develop brand addiction. Mainolfi (2020) reported that materialism had a positive relationship with brand consciousness, intentions to buy foreign luxury products online, and bandwagon luxury consumption behaviour. Materialism has also been examined in relation to consumer ethics. Most studies on this subject indicate that these two factors are negatively related and may be considered competing orientations (Ryoo et al. 2020). There are also studies, though fewer, on the effect of materialism on consumers' pro-environmental behaviours (Wang et al. 2019; Alzubaidi et al. 2021).

Materialism is typically defined as the importance ascribed to the ownership and acquisition of material goods as a means of reaching important life goals (Lindblom et al. 2018). According to the general understanding, materialistic life, "characterized by pursuing possessions, image, and status, has always been looked upon as self-interested and unkind" (Wang et al. 2019, p. 1); nevertheless, materialism has not always been regarded as problematic by researchers (Ryoo et al. 2020). For instance, Pandelaere (2016, p. 36) pointed out that "everybody is to some extent materialistic, and materialistic consumption may not necessarily be bad". In view of the materialists' established expectations for a transformation of life through consumption (Donnelly et al. 2013), in this study, materialism is defined as a general focus on the possession of material goods aimed at achieving success, centrality, and happiness (Richins 2004). To date, the number of studies which have investigated the influence of materialism on overall SCB is limited. One of the few empirical studies that tackled the link between these constructs was the study conducted by Dong et al. (2018). They tested the moderating effect of materialistic values but not the indirect effect of materialism on SCB. In addressing these gaps in the literature, the following hypothesis was formulated:
