5th Edition D&D doesn’t have a surprise round.
Nor does 5e have a surprised condition:

But, that doesn’t mean we can’t pretend it does. After all, pretending is what we’re good at.
To be clear, we’re not doing this to change mechanics. We’re making up terms to understand rules easier.
New Terms
Understanding how surprise works in 5e is a lot easier if we relate how it works to the existing game mechanics. Namely, rounds of combat and character conditions. So, let’s define new terms that work in these spaces.
Surprise Round. If any creatures are surprised, the first round of combat is called the “surprise round.”
Note: Alternatively, you could say that the 1st round is always the surprise round, and skip it if no creatures are surprised. It works out the same.
Surprised Condition. Creatures who are surprised have the “surprised” condition which prevents them from moving, acting, or reacting. The surprised condition ends for a creature at the end of their turn in the “surprise round.”
New Rule
By integrating these terms into the existing rule, we can preserve the existing mechanic while avoiding confusion for folks expecting a surprise round. We don’t need to change that much text.

Why Do This?
Players are used to having a surprise round (and often a surprised condition)! Players coming from 3rd Edition, 4th Edition, or Pathfinder expect that the first round of combat is a surprise round. Leaning on familiar terminology can help players with legacy knowledge transition to 5e.
When you don’t have a surprise round, you run a greater risk of players trying to do pull off actions before combat begins. By clearly defining what happens when creatures are surprised, you define a niche for that narrative to settle in. While this is an adjudication issue, having a clearly defined rule can alleviate those issues at a table.
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Funny, we’ve had surprise rounds all along in our D&D 5e game. Had no idea it wasn’t in the rules. Doesn’t come up often though. Great post.
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I agree, all of the debate about whether there is a surprise round/condition ignores that the rules essentially create those exact things. I don’t think there needs to be a formal version of both, but ONE of them should have been formalized – I prefer the condition, since every participant in the combat may or may not be surprised.
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Reblogged this on DDOCentral.
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I think the other oddity is what to do with the unsurprised character(s) who’s initiative is before the surprising creatures, that aren’t seen or who initiate combat on their turn.
I think this does a good job explaining the RAW.
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