360 degree feedback is widely used by employing organisations but peoples' views of how successful it is vary from individual to individual and from organisation to organisation. Successful experiences of 360 degree feedback can have a powerful effect on performance, retention and development. When 360 degree feedback is unsuccessful within organisations there appears to be a damaging effect on employee engagement factors like motivation, organisational commitment and morale. It is therefore important to gain a better understanding of what differentiates more successful experiences of360 degree feedback from less successful ones. This thesis seeks to answer the question, what makes the difference between 360 degree feedback experiences perceived by participants as successful and those that are not? The research looked at 11 case studies. Each case is a separate organisation. 84 participants were interviewed across the organisations. This provided the opportunity to see 360 degree feedback working in different settings. Using a grounded theory approach, interview transcripts were coded and emergent themes identified through intra-case analysis and further refmed by inter-case comparisons. Finally, existing research into culture and feedback were examined to explore whether they could be applied to these fmdings. Individual reactions to 360 degree feedback are affected by several interacting factors, namely; Feedback Intervention Theory, Feedback Culture, Leader-Member Exchange, Perceived Organisational Support and Organisational Justice. A 'virtuous circle' model was developed ofthe interactions between these factors. If all the factors of the proposed model are present and working together, the factor which seems to have most influence on overall success is the availability and quality of dialogue between the employee and the person facilitating the feedback. The general consensus amongst researchers and practitioners in the 360 degree feedback field is that 360 degree feedback works best in a 'supportive environment'. How much support is provided varies across organisations. The model developed in this thesis casts light on the parameters of that supportive environment and the relationships between them. The combination of interactions between the identified factors constitutes the overall environment of support perceived by the employee as they experience the 360 degree feedback process.