Businesses are increasingly using social media for crisis communication messages, and so do employees. Given the special relationship with employees, organisations should pay attention to understanding employee communication behaviour (ECB) during an organisational crisis. Drawing from the Situation Crisis Communication Theory (SCCT) and the perspective of employees as active participants in crisis communication, this study proposes an evidence-based employee-focused conceptual framework of the anticipated ECBs on social media during an organisational crisis and in response to crisis type and the crisis response strategy utilized by organisations. This research aims to examine the impact of crisis types and crisis response strategies on employee communication behaviour outcomes in social media. The research employs a 2 (crisis type: victim crisis or preventable crisis) * 2 (crisis response strategy: accommodative or defensive) qualitative experimental design. 36 in-depth semi-structured interviews were conducted in Kuwait with employees working in different industries in the private sector to investigate: 1) ECB on social media in response to defensive and accommodative crisis response strategies in a preventable crisis type, 2) ECB on social media in response to defensive and accommodative crisis response strategies in a victim crisis type, and 3)Employee-organisation relationship (EOR) influence on ECB on social media during an organisational crisis. This research argues that the anticipated ECB is within four classifications 1) Proactive advocacy ECB, 2) Reactive advocacy ECB, 3) neutral ECB, and 4) Adversary ECB. The findings show that employees are more likely to engage in advocacy ECB if the crisis response is informative, regardless of the crisis type. An adversary ECB is expected when the organisation faces a preventable crisis type and utilizes a defensive response strategy. Additionally, a positive EOR encourages a more advocacy ECB.