Professional development has long been viewed as crucial to sustained improvement in the quality of primary science education. This paper considers professional development beyond the context of a specific program by examining how the science teaching efficacy beliefs and practices vary between teachers who both have and have not engaged with science professional development. This paper reports on a primarily quantitative study wherein a sample of 206 Australian public primary educators responded to an online survey capturing demographic, science teaching efficacy and science teaching practice data. Quantitative data were analysed via descriptive, ANOVA and Chi Square analyses. The supplementary qualitative data were analysed thematically. More participants reportedly not participating in science professional development (n=128) than those that did (n=78), with teachers based in non-metropolitan and disadvantaged schools being proportionally overrepresented in the "No PD" group. The results showed that teachers who reportedly engaged with science professional development showed significantly higher scores on measures of science teaching efficacy, science teaching approaches and curriculum coverage. Professional development attendees were also more likely to use science teaching approaches aligned with the broader goal of improving students' scientific literacy. This research has implications for increasing access to science professional development opportunities for primary educators. It also shows that the benefits commonly associated with specific professional development programs cannot be solely attributed to the characteristics of teachers willing to pursue such opportunities because the non-attendees in this study were still engaged and confident enough to participate in this research project.