Purpose The aim of this study was to assess knowledge regarding cataract and associated factors among adults in Gondar town Northwest Ethiopia. Methods A community-based cross-sectional study was conducted on 836 adults age ≥18years, using multi-stage systematic random sampling technique, in Gondar town Northwest Ethiopia from April 15-May 7, 2017. Data were collected using pre-tested structured questionnaires through face to face interview. The collected data was entered to Epi info version 7 and analyzed using SPSS version 20. Binary logistic regression was used to identify associated factors. Those variables with p-value <0.05 and confidence interval ≠ 1 in multivariable logistic regression were considered as statistically significant factors for knowledge regarding cataract. Result Among 845 eligible adults, 98.9% (836) of them were fully participated. The median age of participants was 28 years with an interquartile range of 17 years. Of the total participants, 67.2% (562) of them had awareness about cataract [95% CI, 63.8–70.2]. Among 562 participants, 61.7% of them had good knowledge about cataract [95% CI, 57.5–66.00]. It was also found that higher level of education [AOR = 2.86, 95%CI: 1.37–5.96], higher family monthly income [AOR = 1.92, 95%CI: 1.03–3.57], having previous eye examination [AOR = 1.53, 95% CI: 1.02–2.31] and positive family history of cataract [AOR = 1.76, 95%CI: 1.03–3.01] were positively associated with good knowledge. Conclusion Significant portion of the participants had good knowledge about cataract, which was positively associated with higher level of education, higher family monthly income, presence of previous eye examination and positive family history of cataract. However, significant knowledge gap regarding the risk factors and prevention strategies was recognized. Hence, it might be logical to pay special attention in prospering knowledge on how to prevent the occurrence of the disease.