Objectives. To compare the association of California Proposition 56 (Prop 56), which increased the cigarette tax by $2 per pack beginning on April 1, 2017, with smoking behavior among low- and high-income adults.Methods. Drawing on a sample of 17 206 low-income and 21 324 high-income adults aged 21 years or older from the 2012 to 2018 California Behavioral Risk Factor Surveillance System data, we explored 2 outcomes: current smoking prevalence and smoking intensity (average number of cigarettes per day among current smokers). For each income group, we estimated a multivariable logistic regression to analyze the association of Prop 56 with smoking prevalence and a multivariable linear regression to analyze the association of Prop 56 with smoking intensity.Results. Although we observed no association between smoking intensity and Prop 56, we found a statistically significant decline in smoking prevalence among low-income adults following Prop 56. No such association was found among the high-income group.Conclusions. Given that low-income Californians smoke cigarettes at greater rates than those with higher incomes, our results provide evidence that Prop 56 is likely to reduce income disparities in cigarette smoking in California.