Background: Occupational hazards remain a major global public health concern, with a disproportionate burden in the informal sector of low- and middle-income countries. Automobile mechanics are frequently exposed to multiple workplace hazards, yet gaps persist between knowledge and safe practices. Aim: To assess occupational health knowledge, attitudes, safety practices, and associated factors among automobile mechanics in Ikeja Local Government Area, Lagos State, Nigeria. Materials and Methods: A cross-sectional study was conducted among 196 automobile mechanics selected using a multistage sampling technique. Data were collected using an interviewer-administered structured questionnaire covering sociodemographic characteristics, knowledge, attitudes, and safety practices. Data were analyzed using Epi Info (version 2017). Descriptive statistics were computed, and associations were tested using the chi-square test at a significance level of p < 0.05. Results: The mean age of respondents was 31.66 ± 12.6 years, with the majority being male (99.0%) and Yoruba (82.5%). Most respondents demonstrated good knowledge of occupational hazards (82.7%) and positive attitudes toward safety practices (68.9%). High awareness was observed regarding risks such as exposure to harmful substances (88.8%), inhalation of exhaust fumes (95.4%), and manual lifting injuries (92.3%). However, only 48.0% exhibited good safety practices. While 70.9% reported regular workplace cleaning and 56.1% practiced hand hygiene, the use of personal protective equipment was inconsistent. Ethnic group was significantly associated with knowledge of occupational hazards (p = 0.01), whereas other sociodemographic factors were not. Conclusion: Although knowledge and attitudes toward occupational hazards were generally good, safety practices among automobile mechanics were suboptimal. Targeted interventions focusing on behavioral change, improved access to protective equipment, and strengthened occupational health policies are recommended.