The inadequacy of information related to green purchase intention makes it essential for marketers to understand consumer behaviour towards green advertising, especially in Indonesia, where the trend is still new. Acknowledging this research gap, this study aimed to investigate the influence of different green ads by testing whether the ads generate green purchase intention by shaping advertising attitudes. In addition, the moderating role of high or low levels of the participants' environmental concern is also taken into account. This research compares the effects of four types of advertisements: an active green ad promoting the environmental benefits of a product, an emotional green ad employing a visual representation of pleasant natural scenery, a combined-type green ad that unites both functional and emotional attributes, and a control ad. Data collection through online questionnaires was obtained from 143 Indonesian youth, and this was done by way of a convenience sampling approach. Using separate univariate regression analysis, the findings of the experimental study suggest that functional, emotional and combined-type green ads all significantly enhance green purchase intention by shaping ad attitudes, where the active ad displays itself as the most effective appeal out of the rest. These effects depend on the participants' level of environmental concern, shown by the significant moderating role of deep environmental concern towards functional ads and the significant moderating role of low environmental concern towards emotional ads. This research has great marketing implications as many inferences have been made from the gaps and overlap from previous literature.