The Free-to-Play model has become popular in the gaming industry during the last decade. Games are offered for free, where additional content can be purchased. Different monetization features are used within Free-to-Play games to generate revenue. These features have been seen as problematic, especially when children are the players. A limited number of studies have highlighted the problem of these games, and little research has looked into the critical factors of Free-to-Play games and children. This research aims to identify the most critical factors towards creating suitable Free-to-Play games for children. We performed an exploratory study with 15 developers of Free-to-Play and/or children’s games and three domain experts. Data was gathered using semi-structured interviews. A thematic analysis was undertaken to analyze the transcribed interviews and discover themes and patterns across our data set to answer the research question adequately. We identified five crucial factors to consider when developing Free-to-Play games for children: 1) exploiting psychological behavior, 2) game play and user interface, 3) choosing features, 4) customize the development process to children, and 5) responsibility.