In recent years, there has been a strong interest in developing Creativity Support Tools for many exciting areas of research such as art and music. Yet few such tools have been developed to support creativity in advertising. This is unusual since advertising, like art and music, is a highly creative endeavour of the human mind. The goal of advertising is to transform a communicational objective of a product or a service into a creative idea. A tool that would enhance the development of creative ideas in advertising would be highly beneficial for the advertising industry and possibly shed light on the mystery behind creativity. In this thesis, I developed Creative Pad, a new Creativity Support Tool to assist advertising creative in generating creative ideas for advertising. In developing Creative Pad, I studied advertising creativity and human creative thinking. I developed a framework for analysing the advertising process, in which the process is viewed as having three distinct phases: a message, an idea, and an execution. A significant implication of this view is that the process for developing ideas for new advertisements and the process of executing those ideas and turning them into creative products are independent. Each step is the result of a significant creative process. Creative Pad is developed to assist in the development of creative ideas for new advertisements. To assist this creativity, relevant triggers are needed. Research has shown that individuals with high associative skills produce more creative advertising. Creative Pad supports the associative skills of the advertising creative and exploits the use of the Internet as a dynamic database. It finds words and sentences related to the original communicational objective, providing relevant triggers for the associative creative process in the minds of the advertising creative. Several experiments using Creative Pad were conducted with advertising creative and students with no advertising background. The results show that Creative Pad supports the generation of new ideas in two ways. First, and most important, all the subjects were able to develop interesting new ideas. In particular, the advertising creative were able to design a sketch of the advertisement from ideas generated using Creative Pad. Second, I was able to find a connection between the triggers, the words and sentences selected by the user during the creative process, and the ideas generated. Although the connection might be considered a weak one, it nonetheless demonstrates that a connection exists between the ideas developed by the advertising creative and those suggested by Creative Pad.