Background: The survival of horses diagnosed with critical colic relies on rapid and effective decision-making by owner and veterinary practitioner. Objectives: To explore horse owners’ and veterinary practitioners’ experiences of decision-making for critical cases of equine colic. Methods: A phenomenological approach was taken. Individual, semi-structured telephone interviews were conducted with 14 horse owners and 13 veterinary practitioners (vets) who had experienced a critical decision (referral or euthanasia) for a horse with colic. A purposive, convenience sample of participants was recruited. Sessions explored participant’s experience of colic, including recognition, help-seeking behaviour, and challenges. Thematic analysis was performed on collected data. Results: Four over-arching themes were identified; ‘head’, ‘heart’, ‘practicalities’ and ‘impact’. Owners acknowledged responsibility for their horse’s welfare but had different perspectives to vets on the importance of finance (‘head’). Both vets and owners described how the horse-human relationship (‘heart’) often led to conflict during decision-making. The vet-client relationship was influential on decision-making for both owners and vets; involving other people in decision-making was described both positively and negatively by participants (‘heart’). ‘Practicalities’, such as lack of preparedness, transport issues and adverse weather conditions, were identified by both owners and vets as barriers. Owners described a ‘rollercoaster’ of emotions after a critical decision, with profound impacts on their mental wellbeing, feelings of guilt, and long term changes in behaviour (‘impact’), and a lack of support to manage these feelings. Main Limitations: Small sample size. Conclusions: This study describes stakeholder decision-making during critical cases of equine colic. Factors that commonly influenced decisions included an owner’s previous knowledge and beliefs, social pressures, logistics, and the relationship between owner and vet. The study highlighted long term impacts on the owner, including their management and decisions for subsequent horses. These factors should be considered and included in shared decision-making for critical cases of colic.