Purpose In the general population, poor sleep quality and short sleep duration are associated with a higher body mass index (BMI) and waist circumference (WC), and an unhealthy diet. The aim of this study was to assess if the association between sleep quality and duration and BMI, WC, and diet quality also exists among colorectal cancer (CRC) survivors, as many CRC survivors have an unhealthy weight and diet. Methods Cross-sectional data from a longitudinal CRC cohort were used. In this study, survivors were 4–13 years post diagnosis. The Pittsburgh Sleep Quality Index (PSQI) was used to assess both sleep quality and sleep duration. Diet quality was assessed by scoring adherence (low, moderate, high) to the 2007 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) recommendations of five food groups and nutrients: fruit and vegetables, dietary fiber, red and processed meat, alcoholic beverages, and sugary drinks, using a brief diet screener. BMI and WC were self-measured. Associations were analyzed by multivariable linear and multinomial logistic regression analyses. Results Among 1002 CRC survivors, 23% reported poor sleep quality (PSQI score ≥ 8) and 24% reported short sleep duration (≤ 6 h). No associations between sleep and BMI, WC, and diet quality were found. Conclusion Sleep problems are common in long-term CRC survivors; however, sleep quality and duration was not associated with BMI, WC, and diet quality in this population. It is unknown why the results differ from findings in the general population.