The rock ptarmigan (Lagopus muta) is a popular game bird in Iceland, but the population has endured a long-term decline. A hunting ban was enforced in 2003, but 2 years later hunting was allowed again with added restrictions. The aim of this study was to investigate the effects of a change in hunting regulations on the ptarmigan population in northeast Iceland, 1998–2013, using a population reconstruction model and to estimate the abundance of juveniles and adults, natural survival, and harvest mortality. The estimated abundance at the beginning of the hunting season ranged from 42,000 (95% CI = 36,000–49,000) birds in 2002 to 158,000 (95% CI = 105,000–250,000) in 1998. The natural survival of adult rock ptarmigan was density dependent and ranged from 36% to 65% (95% CI = 30–75%). Survival for juveniles was constant and was estimated to be 19% (95% CI = 18–20%). We included a change point in the model to account for a change in the harvest mortality that could have occurred with the changes in the hunting regulations. The results indicated that the change in hunting regulations did reduce ptarmigan harvest mortality and changed the harvest strategies of hunters. Inclusion of a change point in models is useful for managers to test if a change in regulations had an effect on the target population. © 2018 The Wildlife Society.