This study examines individual responses to change and their influence on the success of organizational change initiatives. I used a grounded theory methodology to identify the key factors that influenced individual responses to change during the implementation of a large-scale change initiative at five business units in a $900 million manufacturing organization. I found that people make sense of organizational change efforts based on how the change either enhances or diminishes their individual and organizational identity. As people engage in this sensemaking process, they interpret these changes through four aspects of trust: trust in organization, trust in leadership, trust in process, and trust in outcome. To the extent that they believe that the organization, as an entity, acts in the collective's best interest and is competent, they will trust in the organization. To the extent that they believe that the leadership of the organization will act competently and with behavioral integrity, they will trust in their leadership. To the extent that they believe that the process is fair and that their interests are represented, they will trust in the process. To the extent that they believe that the outcome of the change will be beneficial and that the organization is capable of pulling it off, they will trust in outcome. Combined, these four trusts influence individual responses to change. In chapter 5, I introduce the 4 Trusts Model. The model incorporates my findings into a useful tool for managers. I conclude this dissertation by offering implications for research and practice.