This article is entitled “Refusal Strategies to Invitation in Short Message Service Medium by the Indonesian and Sundanese Speakers”. The method used in this research is the qualitative-descriptive method, with digital data collecting technique. The purposes of this research are to analyse the invitation strategies, to analyse the refusal strategies, and to analyse the refusal trajectories found in one refusal process. Of all the 12 obtained data, it can be seen that the invitation strategy used mostly by the inviters is the conventionally indirect hearer-based condition, i.e. willingness. Then, the refusal strategy used mostly by the invitees is explanation. The mostly appear refusal sequences in one refusal process is Head Act and Post-refusal.