Purpose This study explores the concept social insurance literacy (SIL) and corresponding questionnaire (SILQ) among workers receiving disability benefits and the comprehensibility of the social security institute (SSI), and examines associations with socio-economic characteristics. Methods 1753 panel members of the Dutch SSI were approached to complete the SILQ-NL37. This measure was based on the original SILQ. The SILQ-NL37 contains domains for obtaining, understanding and acting upon information for both individual SIL and system comprehensibility. A higher score means better SIL or comprehensibility. Data on age, gender, education, living situation, Dutch skills and time receiving disability benefits were also collected. With k-means clustering, groups with adequate and limited SIL were created. Associations with socio-economic characteristics were examined with independent t-tests and linear regression analyses for both the total scores and within domain scores. Cronbach α and Spearman rho’s indicated measurement properties were good to acceptable for the SILQ-NL37. Results Thirty-five percent of the 567 participants were in the group with limited SIL. Higher individual SILQ-NL37 scores were associated with having a partner (p = 0.018) and northeastern living region (p = 0.031). Higher scores for obtaining (p = 0.041) and understanding (p = 0.049) information were associated with female sex, and for acting on information with younger age (p = 0.020). People with limited Dutch skills (p = 0.063) and a partner (p = 0.085) rated system comprehensibility higher. Conclusions According to the SILQ-NL37 scores, about 35% of the panel members have limited ability to obtain, understand and act upon social insurance systems information. Limited SIL is associated with several socio-economic factors. Future researches should study the concept in a more representative sample, and in different countries and social insurance contexts.