Introduction:
Smoking is undoubtedly one of the major markers of and contributors to social disadvantage, and reducing smoking-related disparities is a priority for tobacco control. This research explores changes over time in smoking prevalence and quitting by socioeconomic status (SES) in Australia, and whether there are current disparities in uptake, quitting, and use of cessation aids.

Methods:
Analysis of data from Australian National Drug Strategy Household Survey 2001–2016 by quintile of disadvantage.

Results:
Since 2001, there has been a significant linear decline in smoking prevalence for all SES groups, and the absolute gap in smoking prevalence between the most and least disadvantaged stayed fairly constant for the decade 2004–2013 at about 14%, before narrowing to about 12% in 2016. While there has been a significant increase in never smoker prevalence among all groups, the proportion of adult ever-smokers quitting has significantly increased in all groups except the most disadvantaged quintile. In 2016, although the most disadvantaged smokers were equally likely to make a quit attempt, and equally or more likely to use quit aids, success was significantly lower than among more advantaged groups. Further, the most disadvantaged ex-smokers took significantly longer to quit after taking up smoking, placing them at greater risk for smoking-related disease.

Conclusions:
With uptake decreasing among all groups, socioeconomic disparities in smoking appear to be explained by disadvantaged smokers taking longer to quit, or not quitting at all. Low socioeconomic groups are having less success quitting, despite being just as likely to attempt to quit, and just as likely to use cessation aids. More intensive and/or extended cessation interventions, and continuing with evidence-based population-wide strategies that reduce socioeconomic inequalities in smoking, may be required to assist such smokers.

Funding:
Staff salary costs provided: i. through a grant from the Department of Health for the Tobacco in Australia: facts and issues project; ii. through funding for research of secondary national data sets provided to the Centre for Behavioural Research in Cancer by Cancer Council Research; and for policy research provided to Quit Victoria by VicHealth (the Victorian Health Promotion Foundation).