Introduction – Plastic packaging poses significant challenges to environmental sustainability. Its widespread presence in packaging components across all industries contributes extensively to global environmental degradation. Therefore, the purpose of this thesis is to investigate what key factors influence environmental sustainability of plastic packaging components, to understand how companies in the consumer market can improve circularity. Methodology – To achieve this purpose, the study employed a deductive research approach. The key factors were initially identified through an extensive theoretical framework. Following this, a qualitative study was conducted, involving semi-structured interviews with key stakeholders from the cosmetics industry. The data collected was analysed using thematic analysis, allowing for a comparison of theoretical insights with empirical observations. Results – The theoretical analysis identified five key factors influencing the environmental sustainability of plastic packaging: intrinsic properties of plastic, challenges of finding alternative materials, packaging design, the role of consumers, and legislation and regulation. The empirical findings reaffirmed these factors, with notable adjustments: the first two factors were combined into a single category due to their interrelated nature in practice, and cost, which initially was part of the factor “challenges of finding alternative materials”, was elevated as a distinct factor given its critical importance highlighted by interviewees. Conclusions – The study concludes that enhancing circularity in plastic packaging requires efforts focused on reducing the use of new plastics, improving recyclability through packaging design such as modular and mono-materials packaging components. Finally, engaging consumers effectively to adopt environmental sustainability practices, such as recycling, plays a key role in enhancing the circularity of plastic packaging. Implications – The results of this thesis can be used to help companies minimize the environmental impact of their plastic packaging and guide new research approaches.