The Detroit Lions could have lost to many different opponents, so the answer depends on which game, week, or season you are asking about.

Right now, it is not possible to see your full context (for example, whether you meant:

  • Their last game of the 2025 season
  • A specific playoff game in a past year
  • A particular “big game” everyone is talking about this week

Because of that, any specific name given (like “they lost to the Bears/Packers/49ers”) would just be a guess and could be wrong.

What you can clarify

If you tell more detail, the answer can be exact, for example:

  • “Who did the Lions lose to in their last game this season?”
  • “Who did the Lions lose to in the playoffs?”
  • “Who did the Lions lose to on Sunday / on Thanksgiving?”

Right now, with no extra detail, the only accurate answer is:

The opponent cannot be identified without knowing which specific Lions game or season you mean.

TL;DR: “Who did the Lions lose to?” is too vague; there are multiple possibilities, and the exact team depends on the specific game or season you have in mind.

Information gathered from public forums or data available on the internet and portrayed here.