In 2012, the Government of Indonesia and UNICEF launched a project within eastern provinces of Indonesia to scale up and strengthen a national hygiene and sanitation program called ‘Sanitasi Total Berbasis Masyarakat’. A formative study prior to the project was conducted to characterize sanitation and hygiene knowledge, attitudes, and practices (KAP) among 1,700 households in six rural Indonesian districts in 2014. Separate multivariate analyses for toilet ownership (outcome 1) and improved sanitation (outcome 2) were conducted with generalized linear models to assess the association between potential determinants and sanitation outcomes. Respondents who agreed that most people do not have a toilet in their community were associated with lower levels of toilet ownership compared to respondents who disagreed with the statement (p < 0.001). The perception that building a toilet is expensive was also associated with reduced toilet ownership in contrast to respondents without this perception (p < 0.001). Embarrassment and convenience were associated with ownership of improved sanitation versus those with shared or unimproved toilets. The study suggests that social norms play an important role in changing sanitation behaviors. Future research should aim to clarify the extent to which norms and other psychosocial factors can be used to influence sanitation practices.