‘Cancer control and early detection’ is one of the priority programs of the World Health Organization. This quasi-experimental study aimed to investigate the effect of educational intervention, based on the Protection Motivation Theory (PMT), on awareness and early detection behaviours of breast cancer (BC) in women. The eligible women were randomly selected through electronic health records, and divided into the intervention (IG) (n = 45) and control groups (CG) (n = 45). Data were collected in three phases: baseline (T1), immediately (T2) and two-month (T3) after the PMT-based intervention using four questionnaires of Demographic-Clinical Information, Awareness of BC Warning Signs, Awareness of BC Early Detection Behaviours and Modified Early Cancer Detection Behaviours – BC version. Results showed that the PMT-based education influenced the awareness and behaviours of participants in the IG group compared with the CG over time (p < 0.001). The mean and standard deviation of variables improved in the IG in comparison to the CG from T1 to T3: ‘awareness of BC warning signs’ [IG: (T1: 68.50 ± 5.47) to (T3: 89.40 ± 3.50)] [CG: (T1: 69.70 ± 5.87) to (T3: 67.40 ± 2.42)], ‘awareness of early detection behaviours’ [IG: (T1: 78.65 ± 4.47) to (T3: 89.55 ± 4.74)] [CG: (T1: 79.20 ± 5.45) to (T3: 84.10 ± 2.89)] and ‘protection behaviours’ [IG: (T1: 65.01 ± 23.99) to (T3: 98.15 ± 12.20)] [CG: (T1: 56.94 ± 20.85) to (T3: 57.68 ± 21.01)]. Thus, women in this context should be motivated and empowered towards protective health behaviours for early detection of BC. It is suggested that healthcare providers develop PMT-based programs for BC early detection in women in different settings of the community.