The purpose of the article is to determine how personality traits (extraversion, neuroticism, conscientiousness, agreeableness and openness to experience) affect organizational citizenship behaviors for the environment (OCBE), especially in the context of energy saving. The purpose is also to verify the hypothesis that this impact is significantly moderated by individuals’ demographic characteristic (sex, age, length of service, work type and economic sector of employment). To achieve the purposes, a survey was conducted in 2020 on 454 working people from Poland. The analysis was based on structural equation modeling (SEM). The research model assumed that particular types of personality affect direct and indirect OCBEs, including energy-saving patterns. The model also included the aforementioned demographic characteristics of respondents. I proved that personality traits have a significant impact on direct and indirect organizational citizenship behaviors for the environment. In the case of direct OCBEs, the energy-saving items that were most significantly affected by employee personality were: I am a person who turns off my lights when leaving my office for any reason; I am a person who turns off the lights in a vacant room; I am a person who makes sure all of the lights are turned off if I am the last to leave. The strongest predicators were Neuroticism (negative relationship) and Agreeableness (positive relationship) for direct OCBE, but Extraversion (positive relationship) and Agreeableness (negative relationship) for indirect OCBE. The impact of an individual’s personality on OCBE was significantly moderated mainly for indirect behaviors. This applied to all the analyzed demographic variables, but it was stronger for women, employees aged up to 40 years, those with 10 years or more experience, office/clerical workers, and public sector employees. The article discusses the theoretical framework, research limitations, future research directions and practical implications.