The most well-known theories about organisational justice explain how employees perceive fairness within an organisation and how this perception influences their behaviour (Tran, 2025). Organisational justice is commonly divided into three dimensions such as distributive justice, which refers to the fairness of outcomes such as pay or promotions (Donkor & Segbenya, 2023); procedural justice, which concerns the fairness and transparency of the processes used to determine those outcomes (Vaishampayan et al., 2023); and interactional justice, which focuses on the fairness of interpersonal treatment, including respect and clear communication (Kiura & Kim, 2023). Organisational justice is grounded in two key theoretical perspectives, namely Social Exchange Theory (Blau, 1964) and Equity Theory (Adams, 1963).

Social exchange theory proposes that when employees perceive fair treatment, they feel obligated to reciprocate with positive attitudes and behaviours, such as trust, commitment and OCB (Lavelle et al., 2023). Equity theory focuses more specifically on how employees compare their input, which is the outcome ratio with that of others in the organisation (Tavoletti et al., 2024). This implies that when employees perceive an imbalance, for instance, feeling under-rewarded for their effort compared to colleagues, they are more likely to withdraw their effort altogether. Together, both theories explain why perceptions of distributive, procedural and interactional justice are crucial for building trust and sustaining positive discretionary behaviours like OCB in organisations (Hoare, 2021).

Organisational citizenship behaviour skills are important in academic institutions (Ramalakshmi & Ravindran, 2021). Organisational citizenship behaviour refers to voluntary and discretionary actions by employees that go beyond their formal job descriptions but support the effective functioning and social environment of the organisation (Hermanto & Srimulyani, 2022). Osman and Yatam (2024) indicate that some examples of OCB include helping colleagues, mentoring students, suggesting improvements and willingly participating in committees or workgroups. Previous research has studied OCB through multiple theoretical viewpoints, with social exchange theory developed by Blau (1964) being one of the most influential (Meira & Hancer, 2021; Wallenburg & Handfield, 2022; Zhu et al., 2023). According to this theory, when employees feel fairly treated and valued by their organisation, they are motivated to reciprocate with positive, extra-role behaviours that benefit the broader workplace (Farid et al., 2023). As such, OCB is often viewed as a visible sign of strong trust and mutual obligation between the employee and the employer (Lu et al., 2024).

The psychological contract focuses on the unwritten set of mutual expectations and perceived promises that shape the relationship between an employer and an employee (Rousseau, 1995).

Unlike formal employment contracts, which specify tangible job terms, the psychological contract includes informal understandings about support, career development opportunities, recognition and fair treatment (Elsouk et al., 2021). Hoye and Kappelides (2021) highlight that employees tend to form beliefs about what their organisation owes them and what they, in turn, owe the organisation in exchange. This implies that when employees perceive that these promises and expectations are fulfilled, they are more likely to engage in positive discretionary behaviours such as OCB (Foroudi & Fakhreddin, 2025). Conversely, Mitchell (2024) reveals that when employees perceive that these obligations have been broken, feelings of betrayal, dissatisfaction and withdrawal can occur. Social exchange theory underpins the concept of the psychological contract by emphasising that employment relationships are built on trust and reciprocity (Blau, 1964). This suggests that when the balance of give-and-take is maintained through the fulfilment of implicit promises, employees are motivated to go beyond their formal roles and contribute to the success of the organisation (Kim, 2024).

Bakeer et al. (2021) found that perceptions of organisational justice are positively associated with OCB. When employees believe that policies, procedures and interactions are fair, they are more likely to trust their organisation, feel valued and reciprocate with discretionary behaviours that support the broader work environment (Kyei-Poku, 2025). In Essien and Ogunola’s (2020) view, fair procedures and fair treatment increase employees’ sense of belonging and loyalty, which motivates them to go beyond their formal roles to help the organisation succeed. This may include helping colleagues to complete tasks, volunteering for extra responsibilities or sharing knowledge to improve team performance (Kumar & Brindha, 2023). In the higher education context, for instance, when academic staff perceive that promotion criteria, resource allocation or workload distribution are applied fairly and transparently, they are more willing to mentor students, support peers or participate actively in departmental activities (Osman & Yatam, 2024). The relationship between organisational justice and OCB is consistently explained through social exchange theory, which suggests that employees respond to fair treatment with positive attitudes and behaviours as a form of reciprocation (Ranjit, 2022). Therefore, promoting fairness in formal policies and daily interactions could be an effective way to encourage OCB among academic employees in higher education institutions. Accordingly, it is hypothesised that higher perceptions of organisational justice will encourage academic employees to engage in discretionary behaviours beyond their formal roles. This informs hypothesis 1.

Foroudi and Fakhreddin (2025) claim that the psychological contract can play a crucial role in shaping employees’ willingness to engage in OCB. This may suggest that when employees believe that their employer honours both the formal and informal promises that form part of the psychological contract, they are more likely to feel valued, trusted and supported, which strengthens their sense of obligation to give back to the organisation in positive ways (Chadha et al., 2025). This sense of reciprocity encourages employees to go beyond their formal job requirements by helping colleagues, offering constructive suggestions or supporting the organisation’s broader mission (Farid et al., 2023; Kim, 2024). Osman and Yatam (2024) add that in the higher education context, this normally includes mentoring students outside scheduled classes, volunteering for academic committees, participating in curriculum development and sharing research resources with peers.

A study conducted by Rysbekova (2023) has shown that when academic employees perceive alignment between what they were promised, such as opportunities for career growth, professional support or recognition and what is actually provided, they tend to demonstrate extra-role behaviours. Conversely, when the psychological contract is perceived as broken or violated, feelings of disappointment and mistrust are likely to discourage such discretionary contributions (Lilly, 2020). The social exchange theory (Blau, 1964) provides a useful lens in the sense that when the mutual obligations within the psychological contract are met, employees feel motivated to reciprocate through OCB, which helps the institution to maintain a positive and supportive work environment (Gardner et al., 2021). Previous studies indicate that fulfilling the psychological contract significantly motivates employees to engage in OCB (Qurtubi, 2025; Rysbekova, 2023). Accordingly, it is proposed that hypothesis 2, states that the psychological contract predicts OCB among academic staff.

An individual’s belief about the mutual obligations that exist between employees and their employer is shaped by formal promises, informal understandings and daily interactions at work (Knapp et al., 2024). Foroudi and Fakhreddin (2025) reveal that when employees perceive that these obligations are met, they tend to respond with positive discretionary behaviours that benefit the organisation. On the other hand, organisational justice focuses on how employees perceive fairness in the workplace, specifically the fairness of outcomes, the procedures used to determine those outcomes and the quality of interpersonal treatment (Donkor & Segbenya, 2023; Kiura & Kim, 2023; Vaishampayan et al., 2023). Tran (2025) adds that these perceptions shape how employees judge whether their contributions are valued and whether they are treated with respect and consistency. While both the psychological contract and organisational justice are recognised as important predictors of OCB, Daouk et al. (2021) suggest that the psychological contract may play a role by strengthening the influence of organisational justice on OCB. In other words, this suggests that psychological contract may serve not only as a direct driver of OCB, but also as a potential moderator that strengthens or buffers the relationship between organisational justice and OCB. When employees perceive that their psychological contract is not harmed, they may overlook minor perceived injustices and still engage in OCB; this is because organisational justice is closely linked to the psychological contract, and unfairness usually signals a breach of psychological contracts (Chaudhary et al., 2022). This points to the possibility that if the psychological contract is breached, even fair processes or outcomes may not be enough to encourage extra-role behaviours. This reasoning underpins hypothesis 3, proposing that the psychological contract is a stronger predictor of OCB than organisational justice.

Building on social exchange theory (Blau, 1964) and equity theory (Adams, 1963), this study proposes that both organisational justice and the psychological contract shape OCB among academic employees in a selected South African higher education institution. While previous researchers such as Essien and Ogunola (2020), Osman and Yatam (2024) and Ranjit (2022) show that perceptions of organisational justice encourage employees to go beyond their formal duties, this study specifically examines whether the psychological contract plays an even stronger role in driving OCB than organisational justice. Based on this background and the main aim of the study, the following hypotheses were formulated:

A quantitative cross-sectional survey design was applied to examine whether the psychological contract predicts OCB more strongly than organisational justice. This approach allowed the researcher to collect numerical data at a single point in time and to analyse statistical relationships between the study variables. The hypothesised relationships among the study variables are illustrated in Figure 1.

Data were collected through a structured questionnaire. The questionnaire included items adapted from existing validated measurement scales reported in the literature to ensure reliability and validity. Closed-ended questions using a Likert-type response format consistent with the original measurement scales were used to capture respondents’ levels of agreement with the statements.

The results reveal that the psychological contract plays a stronger and more direct role in predicting OCB among academic staff than organisational justice. The analyses indicated that organisational justice did not significantly influence OCB, whereas the psychological contract demonstrated a significant positive effect on employees’ discretionary behaviour. These results indicate that hypothesis 1, which proposed that organisational justice predicts OCB, was not supported, while hypothesis 2, which proposed that the psychological contract predicts OCB, was supported. In addition, the results confirm hypothesis 3, which proposed that the psychological contract would be a stronger predictor of OCB than organisational justice. These results contribute to the growing body of research suggesting that while fairness perceptions are important in shaping employee attitudes, the perceived fulfilment of mutual obligations between employees and their organisation may play an even more influential role in encouraging discretionary behaviour.

The results are consistent with previous research by Chahar (2019) and Santos et al. (2024), who found that psychological contract fulfilment strengthens employees’ willingness to contribute beyond their formal job responsibilities. In the context of higher education institutions, where academic employees often perform tasks that extend beyond their contractual duties, the perception that the institution honours its commitments appears to be a key driver of voluntary engagement in organisational activities. From a theoretical perspective, these results can be understood through social exchange theory (Blau, 1964), which suggests that workplace relationships are built on reciprocal exchanges between employees and their organisation. When academic employees perceive that their institution fulfils both explicit and implicit obligations such as providing support, recognition and opportunities for development, they may feel a sense of obligation to reciprocate through behaviours that benefit the organisation. These behaviours often take the form of OCBs such as mentoring students, assisting colleagues and participating in departmental initiatives.

The results can also be interpreted through equity theory (Adams, 1963), which proposes that employees evaluate fairness by comparing their inputs and outcomes within the workplace.

While fairness perceptions remain relevant in shaping employee attitudes, the present results suggest that fairness alone may not be sufficient to motivate discretionary behaviour when compared with the broader relational expectations embedded in the psychological contract. In situations where employees perceive that the organisation honours its commitments, they may still be willing to engage in OCB even when some aspects of organisational justice are perceived as less favourable. The descriptive results further support this interpretation, as respondents reported relatively high perceptions of both the psychological contract and OCB, suggesting that academic employees generally perceived that mutual obligations were fulfilled and that they frequently engaged in extra-role behaviours. Although perceptions of organisational justice were also relatively positive, its lack of a significant predictive effect suggests that fairness alone may not be sufficient to motivate discretionary behaviour in this academic context. Instead, the results indicate that the relational and reciprocal expectations embedded in the psychological contract may play a more decisive role in encouraging academic employees to contribute beyond their formal responsibilities.

The results highlight that the psychological contract has a more substantial influence on OCB than organisational justice. This suggests that university leaders should prioritise strategies that actively maintain and strengthen the psychological contract with academic staff. Practical actions include clear, transparent communication about institutional expectations, realistic goal setting and consistent follow-through on promises related to career progression, recognition, workload management and professional support (Gander, 2023; O’Meara et al., 2016). Such initiatives are likely to promote perceptions that the university honours mutual obligations, which in turn encourages academics to engage in voluntary behaviours that benefit the institution, behaviours such as mentoring students, collaborating with colleagues, participating in departmental committees and supporting institutional initiatives (Sewpersad et al., 2019).

Although organisational justice is traditionally associated with positive workplace behaviours, the non-significant effect in this study indicates that fairness alone may not be enough to motivate extra-role behaviours in this context. Therefore, interventions should focus not only on equitable policies and procedures, but also on the consistent fulfilment of implicit promises and mutual expectations that form the psychological contract. This approach is particularly important in South African universities, where resource constraints, transformation pressures and post-pandemic challenges place additional demands on academic staff.

This study is limited to academic staff at a single South African university and relied on cross-sectional data collected at one point in time. Additionally, convenience sampling was used, which may limit the generalisability of the findings to other higher education institutions.

Future research should replicate this study using random samples across multiple universities to assess whether the relationships hold in different institutional contexts. Longitudinal studies are also recommended to track changes in perceptions of organisational justice and the psychological contract over time and their cumulative impact on OCB.