In this paper, we report an investigation of the association between household density/overcrowding and mood during a COVID-19 lockdown. Data from an Ecuadorian sample (n = 2489) was collected during the extreme lockdown measures imposed by the local government. Our results indicate that there is a negative relationship between household density and the mood of residents. This finding suggests that higher-density living results in lower levels of self-reported mood, which is in line with the typically negative feelings of anxiety and frustration stemming from restrictions on behavior. A post-hoc analysis of our results highlights important insights for different age groups. This analysis shows a statistically significant difference between generations. Specifically, the negative relationship between household density and self-reported mood during quarantine is statistically significant for those born in 1969-1980 and 1994-2010, the so-called X and Z generations, respectively. However, it is not significant for those born in 1949-1968 and 1981-1993, groups known as baby boomers and generation Y, respectively.