Objectives: The COVID-19 pandemic has had serious negative socioeconomic consequences and has led to changes in day-to-day functioning and work organization. The outbreak and subsequent school closures abruptly compelled teachers to switch from classroom instruction to distance education, requiring rapid adaptation to new digital technologies with insufficient support. These unexpected transformations may have affected teachers’ stress levels and, consequently, their mental health and work ability. The purpose of the study was to examine the relationship between challenges at work during the pandemic, subjectively perceived work ability, and the general functioning of teachers of primary and secondary schools. Material and Methods: The study included 370 primary and secondary school teachers from the Łódź Voivodship, Poland. Data were collected online from October 2022 to May 2023, after in-person teaching had resumed. Participants completed an occupational stressor checklist, the single-item Work Ability Score (WAS) derived from the Work Ability Index, the General Functioning Questionnaire, 58 items (GFQ-58), and questions on pandemic-related concerns and threats. Factor structure and associations were examined using factor analyses, non-parametric tests, and binary logistic regression. Results: Work-related stress was associated with lower self-rated work ability and poorer general psychological functioning. Relational and communication difficulties were associated with higher odds of poor or moderate work ability (OR = 1.73, 95% CI: 1.17–2.55). Insufficient organizational and training support, technological barriers and rapid work changes, personal concerns, and an acute COVID-19 infection course were independently associated with higher odds of an elevated GFQ-58 score. Conclusions: The study allowed for the identification of key pandemic-related psychosocial stressors and their associations with teachers’ work ability and general psychological functioning. These findings highlight the importance of organizational support and preparedness during periods of rapid change, while the effectiveness of specific interventions requires further evaluation. Int J Occup Med Environ Health. 2026;39(5)