Introduction: Dental hygienists are well placed to assist their patients to quit smoking. Smoking affects oral health and dental treatments, and hygienists report greater time with patients than dentists with more focus on prevention. However, there has been little research into the extent to which hygienists assist patients to quit smoking and strategies to support them in this role. Methods: A 2-stage survey of Australian dental hygienists was conducted. The first survey measured potential predictors of asking patients about smoking and assisting patients to quit smoking using the Theory of Planned Behavior as a framework. The second survey measured these behaviors in the past week. Structural equation modeling was used to examine predictors of the two behaviors. Results: A total of 362 hygienists returned the fi rst questionnaire. Intentions to ask and assist patients were high. The 273 hygienists who returned the second questionnaire assisted an estimated total of 1,394 patients to quit smoking in 1 week. Predictors within the Theory of Planned Behavior framework explained significant variance in asking (11%) and assisting (29%) behaviors, with self-efficacy the most critical predictor in both cases ( β = .27 and .32, respectively). Conclusions: Dental hygienists may be a viable and willing avenue for addressing smoking. Hygienists may be best supported in this role through increasing skills and confidence around asking sensitively about smoking, building rapport, and assisting patients to quit smoking. Incorporation of smoking status into general history taking and adoption of organizational policies on assisting patients to quit smoking could also be encouraged.