According to the recent report, Marvel Studios and Walt Disney Pictures will reveal the first teaser trailer for the Alan Taylor-directed Thor: The Dark World during the first week of April.
The film is set to explore other realms as Thor fights to restore order across the cosmos. There has been some speculation on when we might see the first trailer, but according to Emileeid, the teaser trailer will premier online on April 2nd and it will eventually be attached to the prints of Shane Black’s Iron Man 3. Other than Evil Dead and Jurassic Park 3D, there is no other big releases that week in theatres, and since this is not confirmed just yet, take it with a grain of salt. (Source)