The construction industry is known as one of the biggest generators of solid waste. Considering this, attention needs to be paid to construction and demolition (C&D) waste. Lebanon has experienced many situations that have increased the generation of C&D waste. Therefore, it is essential to manage C&D waste. This research aims to assess and analyse the importance of waste management plans and their impact on the generation of construction and demolition waste in Lebanon. For this purpose, an extensive literature review has been carried out, and a questionnaire survey consisting of five sections has been developed. Factors were ranked by using 5-point Likert scales. Additionally, four optional open-ended questions were also included in the survey for qualitative data collection. A survey questionnaire was sent to 80 Lebanese experts, and 50 questionnaires were returned. Most of the responses (i.e., consultants and academics) were from the private sector; results showed that respondents to this survey were biased for their expertise. Reliability and ranking analysis were performed on the collected data. It was found that “site management and supervision-related factors” are the main sources of C&D waste. The main barrier to implement 3R was the “lack of awareness and knowledge”, and the most critical success factor was “waste management regulations”. There is lack of data on construction waste in Lebanon. Therefore, there is a need to conduct research on construction waste management in Lebanon, which is the subject of the current investigation. This research is expected to generate benefits for the construction industry in Lebanon and the surrounding region.