Myanmar has gone through major changes since 2010, and this has led Western powers to lift most of the sanctions that they have imposed on the country since 1988. This thesis asks whether the sanctions were instrumental in generating the Myanmar government s decision to reform. Studies on sanctions are generally pessimistic about the prospect of imposed sanctions being successful. Similarly, studies on the effect sanctions against Myanmar did not predict that sanctions would have an effect. Rational choice theory holds that sanctions will be effective if their cost outweigh the cost of compliance. If a target with complete information finds it rational to comply, it will do so when faced with the threat of sanctions, to avoid them being imposed. A target can comply after sanctions are imposed, if it initially miscalculated the likelihood of sanctions or the cost of sanctions, or if it believed that sanctions would be imposed regardless of whether it complied. This thesis seeks to identify whether the sanctions imposed on Myanmar had any effect by considering whether it made, and eventually corrected, any of these miscalculations. The thesis finds that sanctions came to play a role in Myanmar when their relative cost increased more than could have been predicted at the outset. The unexpected increase of the cost was partly because the sender states increased the sanctions incrementally over a large period of time, but it was equally important that sanctions indirectly affected Myanmar through forcing it into a closer relationship with its neighbouring states, particularly China. The increasing Chinese dominance in Myanmar decreased the benefits of status quo to the point where it was rational to comply with the Western demands. The Myanmar government consolidated its power through political reforms, which made it possible for them to comply with demands without sacrificing their security. I term the effect of sanctions an unforeseen success, because neither the sender states nor the target could have predicted the increased relative cost of sanctions through the indirect effects. The findings of this thesis suggest that it would be useful to extend the sanctions theory by including indirect effects of sanctions.