Objective. Previous research suggests that wine glass size affects sales of wine in bars, with more wine purchased when served in larger glasses. The current four studies, conducted in one restaurant (Studies 1&2) and two bars (Studies 3&4) in Cambridge, England, aim to establish the reproducibility of this effect of glass size on sales. A multiple treatment reversal design was used, involving wine being served in sequential fortnightly periods in different sized glasses of the same design (290ml, 350ml, and 450ml). The primary outcome was daily wine volume (ml) sold. Results. Restaurant: Daily wine volume sold was 13% (95% CI: 2%,24%) higher when served with 350ml vs. 290ml glasses in Study 1. A similar direction of effect was seen in Study 2 (6%; 95% CI: -1%,15%). Bars: Daily wine volume sold was 21% (95% CI: 9%,35%) higher when served with 450ml vs. 350ml glasses in Study 3. This effect was not observed in Study 4 (-7%, 95% CI: -16%,3%). Meaningful differences were not demonstrated with any other glass comparison. These results partially replicate previous studies showing that larger glasses increase wine sales. Considerable uncertainty remains about the magnitude of any effect and the contexts in which it might occur.