This study examines how Australian academic librarians perceive effective Web 2.0 tools used to market library services and resources and the factors influencing perceptions of the Web 2.0 tools used. An online survey was sent to 400 academic librarians in 37 Australian universities. The response rate was 57.5%. The qualitative data were analysed using content analysis. The collected quantitative and qualitative data were analysed using descriptive (frequencies, percentages, means, standard deviations) and inferential statistics (ordinal regressions). The key findings show that demographics, human capital and library variables play an important and significant role in predicting librarians' perceptions of effective Web 2.0 tools used to market services and resources. This paper provides a better understanding of academic librarians' attitudes, views as well as effective Web 2.0 tools used to market their services and resources. Librarians can use the results to reflect on the effectiveness of the Web 2.0 tools used, to balance the weight of the factors' influences and to better understand various effective Web 2.0 tools to enable them to market academic library services and resources more effectively in the future.