The topic of this paper is the impact of social network communication on consumer engagement in the context of non-profit organizations. The paper theoretically explores the concepts of social networks, consumer engagement, non-profits, and the connection between them. The aim of the empirical part is to compare the Facebook posts of ideologically opposed non-profit organizations in Croatia and answer questions about what type of post they use, what communication messages are present in their posts and what impact it has on their consumer engagement. Furthermore, it will provide a general comparison between the selected organizations. The chosen non-profit organizations are those which openly express their views on child adoption by same-sex couples. Among the selected associations, Dugine Obitelji and Zagreb Pride advocate, while U ime obitelji and Vigilare oppose such practices. The observed posts were coded according to the type of their communication message, the type of post, the valence of the message and the source of communication. Using statistical one-way analysis of variance, ANOVA conducted a statistical analysis and described a review of the consumer engagement for the observed period. The results showed that no significant differences were observed in the number of negative reactions, positive reactions, number of shares and number of comments depending on the type of post, type of communication message, message valence and communication source. Therefore, an additional ANOVA analysis was conducted in order to examine the total consumer engagement using the following parameters: the sum of positive, negative reactions, the number of comments on the post and the number of times the post was shared. The research showed that the associations U ime obitelji and Vigilare received the most positive reactions to marketing messages which communicated emotional gain. It also showed that the associations Zagreb Pride and Dugine obitelji had the most positive reactions to photo and video content, messages which communicated empowerment of the community and which are positively framed with emotional gain. The most often shared posts were those with messages which communicated rational gain.