The TPB is an effective framework that has been widely applied in textiles and apparel-related topics, such as used apparel donation [16], luxury fashion consumption [22,23], second-hand apparel shopping behavior [19], willingness to buy environmentally friendly apparel [8,21], slow fashion consumption [3], and fashion collaborative consumption [24]. Chi et al. [8] proposed an extended TPB and revealed that attitude, subjective norm, perceived consumer effectiveness, and environmental knowledge significantly affected U.S. consumers’ purchase intentions toward environmentally friendly apparel. Ganak et al. [16] identified that young U.S. consumers’ attitude, subjective norm, and perceived behavior control drove their behavior toward donating used apparel. Chi et al. [3] reported that attitude, perceived behavioral control, willingness to pay, and perceived consumer effectiveness significantly affected U.S. consumers’ willingness to buy slow fashion apparel. McCoy et al. [24] indicated that attitude, subject norm, perceived consumer effectiveness, past environmental behavior, and fashion leadership significantly influenced Gen Z consumers’ intentions to use apparel rental services. The successful applications of TPB in prior studies have proved its versatility and applicability in the present research.

Attitude is a crucial element in shaping consumers’ purchase intentions. It is usually applied to interpret and project consumers’ purchase intentions toward products or services, such as environmentally friendly apparel [8,21]. Eagly and Chaiken [25] defined attitude as a psychological tendency that is expressed by evaluating a particular entity with some degree of favor or disfavor. Attitude has been proven to be one of the most influencing factors to have a positive connection with consumer sustainable consumption willingness and actual behaviors [3,8,24,26]. If a person expects to have a positive experience after purchasing a product or service, they are more likely to form a positive attitude toward the behavior that consequently leads to purchasing behavior [16,19,24].

Ganak et al. [16] stated that we can predict consumers’ recycling behavior from their attitude and intention. The attitude toward sustainability not only affects consumers’ purchase behavior but also influences companies’ sustainable policy and decisions [27]. Sustainable actions should work on both sides of the trading relationship. The sustainability attitude of consumers and firms could potentially alter the trading environment to become more sustainable and healthier [8].

Attitude is influenced by a person’s beliefs about the consequences of the behavior, their values, and past experiences with the behavior. A positive attitude toward sustainable products increases the likelihood of having a strong intent to purchase the products, while a negative attitude reduces it [3,8,21]. Chi et al. [3] stated that consumers with more knowledge about slow fashion products and textile waste show a positive attitude and are consequently inclined to buy slow fashion products. McCoy et al. [24] indicated that attitude is the most influential factor in forming individuals’ willingness to use the environmentally friendly services in the fashion industry.

Subjective norm refers to an individual’s perception of what is considered to be acceptable or normative by significant others, such as friends, family, and peers [28]. Subjective norm is an external factor that could affect whether people are going to carry out a specific behavior [18]. The subjective norm can reveal how much consumers value others’ perspectives in terms of sustainable shopping and how crucial it is to maintain a positive image outside of personal life [29].

People tend to search for a sense of belonging. They are motivated to understand and to follow the norms of groups that we belong to and care about [30]. The reason for people valuing social norms so much is because the way we react to those social regulations could affect the status and place in specific communities [31]. Prior studies found that subjective norm could be a great influencer of purchasing sustainable products but also an incentive for people against doing so under peer pressure [8,16,21].

Nowadays, everyone can be influential on social media by expressing their opinions, insights, experiences, and perspectives with others [32]. It is impossible to isolate ourselves from other people in the age of the internet. How to set a line between ourselves and others is an important issue in modern society. In the literature, there are more researchers supporting the correlation between attitude and intention of behavior than subjective norm and intention of behavior in the TPB model. Kumar [33] stated that there is a relatively weak connection between subjective norm and behavioral intention. McCoy et al. [24] also demonstrated that subjective norm accounts for a lower variance of consumer intention to use fashion rental services than attitude. As society and consumer lifestyle have been evolving quite significantly in recent decades, the way people interact with each other could be changing, so further research is necessary on the relation between subjective norm and behavioral intention.

PBC is defined as one’s perceived extent of how simple or challenging it is to engage in a behavior [34]. The concept indicates that people with resources and skills would increase their intention to perform specific actions [35]. Additionally, it is assumed to reflect the anticipated obstacles and past experiences [18]. Joshi and Rahman [36] identified that PBC positively affects consumers’ green purchase behavior. Kostadinova [37] reported that attitude, subjective norm (SN), and perceived behavioral control (PBC) of the Theory of Planned Behavior are reliable predictors of purchase intention toward environmentally friendly products. Chi et al. [3] indicated that PBC should be investigated in any sustainability product or service adoption studies as perceived control over a behavior affects consumers’ decision making.

Perceived consumer effectiveness was first proposed by Kinnear, Taylor, and Ahmed [38], which can be broadly defined as the level of how consumers believe their efforts can improve or solve the social and environmental problems [39]. People perceiving higher consumer effectiveness on environmental protection show greater concern for environmental issues [21]. PCE is considered as the connection between environmental awareness and eco-conscious consumer behavior [39]. Vermeir and Verbeke [40] indicated that if consumers believe what they do has a certain positive influence on the ecosystem, they will be more likely to promote and purchase environmentally friendly products. Ganak et al. [16] reported that U.S. millennials who are confident about their positive impact on environmental protection are more inclined to recycle their used denim jeans. McCoy et al. [24] also demonstrated that consumers with a higher PCE show a higher likelihood to try fashion rental services instead of purchasing clothing.

Van der Werff, Steg, and Keizer [41] found that it is effective for increasing individual’s environmentally friendly action by reminding them of their past pro-environmental behaviors. Consumers who have more knowledge on environmental issues and possible solutions are more likely to form environmentally friendly behaviors [21]. Thøgersen and Ölander [42] indicated that consumers’ previous behavior in sustainable movement positively affects their future pro-environmental actions. Prior studies reported that consumers show a greater possibility to purchase eco-friendly products if they have conducted environmentally friendly actions in the past [8,24,41,43].

Additionally, the relationship between attitudes and behavior is well established in the previous research [24,41,43]. Lauren, Smith, Louis, and Dean [44] concluded that people exhibiting sustainable behaviors are more likely to adapt their attitudes to correspond with these behaviors. According to Cervellon and Carey [45], purchasing eco-friendly products is the action where consumers express their concerns, while Lundblad and Davies [46] advocated that green consumption improves consumers’ confidence on their contribution to environmental protection. Zheng and Chi [21] reported that the past environmental behavior of a consumer is a good predictor of their attitude toward green consumption. Chi et al. [3] also demonstrated the linkage between past environmental behavior and consumer attitude toward sustainable apparel consumption.