Lifelong learning has become an integral part of educational approaches, aiming to promote continuous learning throughout an individual's life. The purpose of the current literature review is to assess the trends, themes and gaps in lifelong learning for engineers. A comprehensive search was conducted in Google Scholar, ScienceDirect, and Scopus for articles published from 1990. Specific search terms were used to retrieve relevant articles and were determined based on a combination of keywords. The abstracts and titles of the retrieved articles were screened to determine their eligibility for inclusion in this study. A total of 5,342 studies were initially identified. After removing duplicates, the number of studies was reduced to 2,217. Subsequently, the studies were further filtered based on the predefined qualification criteria, resulting in 1,779 studies that underwent abstract and title screening. Ultimately, a total of 28 articles were identified as meeting the predefined eligibility criteria and were considered for the research. These selected articles formed the basis for the thematic analysis and further exploration of the research topic. The studies emphasized the significance of both formal and informal learning and training. Problem-based learning is a crucial component of lifelong learning. This approach encourages deeper understanding, independent thinking, and the development of teamwork and essential skills. Self-directed learning is a prominent competency for lifelong learning. It involves self-reflection, self-regulation, and proactively identifying areas for improvement. A group-based approach is suggested to complement technical knowledge with personal skills and non-technical competencies. Five themes including self-directed learning, coaching and mentoring, problem-based learning, formal and informal learning, and group-based approaches were identified. These concepts should be integrated into the education system and the workplace to support lifelong learning for engineers. [For the full proceedings, see ED652261.]