Abstract: Background: Occupational contact allergy is common in the cleaning industry. Objective: To identify common occupational sensitizers and analyze time trends in type IV sensitization in female cleaners. Methods: Data of 860 female cleaners with occupational dermatitis (OD) patch tested in 58 centers within the Information Network of Departments of Dermatology from 2010 to 2022 were analyzed. The comparison group consisted of 966 female cleaners without OD. Statistical analyses included 95% confidence intervals (CIs) and the exact Cochran–Armitage trend test. Results: Among 860 female cleaners with OD, 729 (84.8%) had hand dermatitis. Most frequent final diagnoses were irritant contact dermatitis (32.8%) and allergic contact dermatitis (25.3%). Compared to female cleaners without OD, higher sensitization rates were found for rubber additives (thiuram mix [8.6%, 95% CI: 6.5–10.7], zinc diethyldithiocarbamate [2.0%, 95% CI: 0.9–3.1], mercapto mix [1.3%, 95% CI: 0.4–2.1]), formaldehyde (2.3%, 95% CI: 1.0–3.6), and hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) (3.0%, 95% CI: 1.5–4.6). Glutaraldehyde sensitization showed a decreasing time trend over the study period and should be further monitored. Conclusions: Rubber additives, preservatives/disinfectants (aldehydes), and HICC are occupationally relevant sensitizers in female cleaners, underscoring the need for targeted prevention strategies and continuous monitoring to protect their health.