I found a number of posts with similar issues: How to change legend position in ggplotly in R Theme(position.legend="none") doesn't work with coord_flip() How to change legend position in ggplotly in R Eventually, I found that legend.position always 'right' in ggplotly, except when legend.position = 'none' so it seems there is no way to fix my issue if I use ggplotly instead of ggplot. Please correct me if I am wrong https://github.com/plotly/plotly.R/issues/1049