RailsGirls is an activity to introduce Ruby and Rails to women, ranging from beginners to programmers familiar with other languages. There are nine events held in Japan so far with more than 300 participants. The speaker first participated RailsGirls Tokyo 2nd as a trainee (aka girl), and then Tokyo 3rd as a coach. In this session, she will introduce what RailsGirls is and how you can contribute to the activity and why you want. Also she will discuss about why we need more women in software engineering and why diversity is necessary.