Since the things considered important for humanity vary among individuals, it can be stated that there are as many definitions of the concept of quality of life as there are individuals. Therefore, there is no scale that evaluates the concept in a general framework or on specific characteristics and has general validity. U.S. News & World Report and The Economist Intelligence Unit, along with Eurofond, are global sources that publish quantitative data on cost of living and quality of life, comparing countries by calculating quality of life scores based on this data. However, the "Quality of Life Index" published by Numbeo since 2012 has become increasingly interesting in recent years. Numbeo, a crowdsourced global resource, determines the quality of life levels in countries within the framework of social, economic, and environmental indicators. With the set of indicators defined by Numbeo, the quality of life levels in countries can be monitored and controlled. In this context, the aim of the study is to evaluate the quality of life levels of OECD countries, which aim to increase their welfare levels by collaborating in areas such as economic growth, development, trade, investment, entrepreneurship, and technology, using the quality of life indicators and data provided by Numbeo. To define a measure of quality of life in terms of specific attributes and to make comparisons among OECD countries, LOPCOW (LOgarithmic Percentage Change-driven Objective Weighting) ve COBRA (COmprehensive Distance Based RAnking) methods from Multi-Criteria Decision-Making techniques were utilised. The most important criteria that play a role in improving the quality of life in OECD countries are the "Traffic Time Index, Real Estate Price-to-Income Ratio, and Cost of Living Index," with the countries having the highest quality of life being Luxembourg, the Netherlands, and Denmark, respectively. Furthermore sensitivity and comparison analyses are made in order to test the validity and reliability of the model.