Does the Toradora OVA fit canonically in the main storyline? I only know about the anime, so I'm basing this question on that. Toradora's anime aired in 2009. In 2011, a side story OVA was released with the Bluray collection of the series, titled "The True Meaning of Bento" (Bento no Gokui).

This side story has little to do with the main plot, so in principle it can probably go in a lot of places in the story. However, I'm wondering if there's a canonical answer for when these events occured (or if they are intended to be canon at all). I don't know if anything similar happens in the light novels or if there has been official commentary on where it falls (preliminary searches all didn't turn anything up), but either of those would be sufficient for this question. 

Is this OVA canon, and if so, when in the story does it occur?
Based off my observations of the Anime i believe that the OVA is set between the end of the Culture Festival as Taiga is acting normal around Kitamura which only occurs after the culture festival, and before the student council election as not only is Minori not awkward around Ryuji or spacing out because of what Ami said to her after Taiga and Sumire's fought one another but also the end of the anime series occurs around winter and right after the elections is Christmas which in Japan is in winter.


   Also it's evident it's still winter when Ryuji and Taiga elope and Taiga moves schools after that


This is also strengthened by the fact that the first OP was used and after the elections is when the second OP started to be used

Given that I would say the OVA occurs between the end of Episode 13 and the start of Episode 15 (as  am accounting the possibility that the OVA is an event that occurred between Episode 14 and 15).

My assumtion is almost spot-on as in art book which came with the limited edition of the series from NISA there is a point at the bottom of page 5 talking about the OVA


  this is the first episode done for "Toradora!" in over 3 years, and the story takes place between episodes 13 and 14 of the TV Series. this episode has a comical bento battle and a heartfelt development, striking a delicious balance between the laughter and drama that "Toradora!" Is best known for.


Bellow is a photo i took of the relevant section, up the top slightly cut off is the same image as what is posted in the question