Background and aims: Alcohol's harm to others (AHTO) has become a key driver of national and international alcohol policy. This study aimed to produce a contemporary, comprehensive estimate of the correlates and harms from others' drinking in 2021 in Australia. Design, setting, participants and measurements: Across Australia, 2574 adults (1380 women; 1172 men) were sampled via two cross-sectional survey modes: a random-digit dial mobile phone sample of 1000 people and 1574 people from the Life in Australia™ panel survey. In 2021 participants were asked about harms they had experienced from the drinking of family, friends, co-workers and the public in the past year. Applying combined sample weights from each mode, bivariable and adjusted multivariable logistic regressions were used to analyse differences in rates of AHTO by participant gender, age, residence in rural or metropolitan regions, country of birth, education and employment. Findings: In 2021, 23.6% reported being negatively affected by strangers' drinking and 21.3% by the drinking of someone they knew, with 34.3% reporting being negatively affected a lot or a little by either; 42.4% of respondents reported specific harms from strangers' drinking. Thus, 48.1% of respondents reported any harm (negative effects or specific harms) from others' drinking. Women, younger people, Australian-born and heavier episodic drinkers reported significantly higher rates of AHTO compared with other respondents. Smaller percentages (7.5%) of participants reported being harmed substantially by others' drinking, including by people they knew (5.8%) or strangers (2.3%). Stratified analyses showed that heavier drinking, furloughed, younger men who were born overseas in English-speaking countries were affected by others' drinking, whereas women were affected regardless of these factors (apart from age). Conclusions: More than one-third of Australian adults appear to have been negatively affected by others' drinking in 2021, with women, younger people and heavier drinkers at greater risk. Substantial harm appears to be more likely to arise from the drinking of people Australians know than from strangers' drinking.