Abstract The paper investigates spillover in the pro-environmental context of Australian consumers’ transition to using reusable bags, and explores its implications for other related environmental behaviours. This study uses a natural time-series design (pre, during and post change measures) to examine a real-world instance of a forced behaviour change incorporating changes in people’s grocery shopping habits and possible subsequent behaviours. The study examines attitudes and behaviours including spillover, environmental lifestyle and moral licencing before (n = 200), during (n = 342) and after (n = 346) the phase out of single-use plastic bags. The definition, operationalisation, and measurement of spillover are also explored. Despite conflicting evidence from previous research, our findings suggest that a forced behaviour change can incidentally result in changes in subsequent related behaviours.