①Background: In 2003 the government of Tanzania enacted the Tobacco Products (Regulation) Act 2003, which, among other things, prohibited smoking in public places. However, smoking has persisted despite the existence of the Act. This study aims to establish the reasons behind the persistence of tobacco smoking in public places. ②Methods: This was a cross-sectional study where data were collected using pre-tested, self-administered questionnaires with both open and closed questions and documentary reviews. The study was conducted in urban, rural and semi-rural areas in three districts located in eastern, central and northern Tanzania. Quantitative data were analyzed using SPSS ver. 15. Qualitative data were analyzed manually using a thematic content approach. ③Results: The study involved 240 participants, of whom 67% were males. Overall smoking prevalence was 26.5% (36.3% for males and 6.4% for females, p<0.05). The prevalence of smoking in rural, urban and semi-rural settings was 34.9%, 28.6% and 36.5% respectively, (p> 0.05). About 40% of the smokers were between 25-35 years old and 52.4% had primary school as their highest level of education. About 56% of participants said they were aware of the Tobacco Regulation Act, but the majority could neither define it nor state the penalties for its infringement. Only 59.5% were aware that tobacco smoking causes lung cancer. About 4 out of 10 cigarette smokers do not adhere to NO SMOKING warnings. ④Conclusions: Cigarette smoking in public places in Tanzania has persisted mainly due to low awareness and passive implementation of the Tobacco Regulation Act, 2003. Other causes are aggressive advertising and promotion by the tobacco industry and insufficient awareness about the health effects associated with tobacco smoking. This study calls for an increase in cigarette taxation, sensitization about the dangers of both smoking and second-hand smoke and active enforcement of the act as immediate intervention strategies.