Consistent and frequent interactions with smartphones have become an increasing tendency in the modern society. Smartphone over-use is among several problems critical and severe as it appears as a dominating element invading the individual and social nature and quality of everyday living leading to less physical and mental interactions with fellow people. Current strategies utilised for promoting smartphone non-use mainly provide successful results within a short-term period. This Master’s thesis presents “GreyZone”, a provocative interaction design, as well as investigates whether this design persistently promotes smartphone non-use over a selected period methodologically by integrating research through design within natural settings. GreyZone is fundamentally designed and constructed by integrating and combining the four provocative aspects aesthetical, conceptual, functional and material as an attempt to promote visibility in order to initiate critical reflection regarding own smartphone usage in-situ. This visibility of the actual usage is provoked as GreyZone restricts the availability of the smartphone to one hour a day. The effectiveness of provocatively promoting smartphone non-use was qualitatively and quantitatively measured throughout a study period involving eight participants with high diversity within the combination, GreyZone was handed out to five participants for 14-20 days. The findings of the investigation clearly showed similarities in the perceptions of GreyZone. The analysis of the gathered data shows large changes in behaviour during the trial period with GreyZone as well as in the weeks following the trial due to its ability to provoke reflection upon both self-selected and invoked interactions with the smartphone. Unfortunately it is a tendency returning back to usual patterns.