The decrease in the average age of marriage and the increase in loneliness among women in Algeria is a phenomenon that is becoming increasingly visible in society. In the coming years, the number of single people will increase. This article analyses the factors leading to increased loneliness among women aged 40 and over in Algeria based on data from the MICS6/2019 survey. The minimum age threshold was chosen because it corresponds to the age after which the probability of first marriage is almost zero based on Algerian statistics. The methodology of this study is stepwise Wald logistic regression. The paper built regression models based on two samples: the first (24,681 women aged 40 and over) and the second (4,329 women aged 50-54). For an empirical study of loneliness among women, it is proposed to analyze the following determinants: type of employment, type of social protection, place of residence, level of education, and age. Based on the results of the research, four main conclusions were formed. First, the odds of being single are 14.1 times and 4.23 times higher among job-seeking and working women, respectively, compared to non-working women. Due to the loss of hope to get married, women choose career development instead of building a family union. Under these conditions, women integrate into the labor market late. Since most of this category is unemployed and not of retirement age, they have low health insurance coverage. Based on this, to create decent living conditions for single women aged 40 and older, it is advisable to launch a program to improve the qualifications of these women, find ways to integrate them into the working environment and provide them with health insurance. Secondly, the long-term trend indicates that loneliness as a psychological phenomenon will increase every year in society, which will, accordingly, contribute to the strengthening of the imbalance in the marriage market. Late marriage and declining fertility are indicators of new patterns of behavior brought about by economic and social change. Thirdly, the level of well-being is also a statistically significant factor influencing the loneliness of women. Middle-class women are 1.27 times more likely to be single than upper-class women. Fourth, the survey revealed significant regional differences. Women in Algeria’s north-eastern and north-central regions are more likely to remain single. These results can be further explored through qualitative research.