Purpose There has been a growing concern about employee silence (ES) within an organization. ES is associated with low creativity and innovativeness, unethical organizational practices, avoidable errors and safety-related issues. The purpose of this study is to evaluate the mediating role of psychological insecurity (PI) in the relationship between leaders’ bullying behaviour (LBB) on defensive (DES) and acquiescent employee silence (AES). Design/methodology/approach Data were collected among police personnel working in Plateau state Nigeria. In all, a total of 350 responses were found useable for further analysis, of the 398 copies of the questionnaire administered. A structural equation modelling technique was used via SMART-PLS version 3.3.3 to test the hypothesized relationship. Findings The findings of this study revealed that leaders’ bullying positively and significantly influences both AES and DES, and PI was found to mediate the relationship between LBB and AES and DES. Originality/value LBB among the police has been under-researched, even when there is clear evidence of its existence. PI explains the mechanism through which LBB influences officers' silence.