Can you have advantage/disadvantage on your Initiative check?

Question

From the rules, it seems that an initiative check is just an ability check. There are numerous effects that give Disadvantage on ability checks, and some that give Advantage.

I don't see it called out anywhere specifically, so should I assume that you can have advantage/disadvantage on these checks as normal?

Some examples; using inspiration to get Advantage on an initiative check, or getting Disadvantage if you're poisoned or exhausted.

(I ask because I'm used to initiative checks being special cases, and also because the Alert feat gives a flat +5 to those checks, when I'd expect it to grant Advantage if that's possible. On the other hand, it doesn't actually say Initiative is anything special.)

Answer 1

Yes

Barbarian's 7th level feature does just that:

Feral Instinct

By 7th level, your instincts are so honed that you have advantage on initiative rolls.

Additionally, if you are surprised at the beginning of combat and aren't incapacitated, you can act normally on your first turn, but only if you enter your rage before doing anything else on that turn.

For a more general understanding, rather than a specific case, the rules for advantage say:

Sometimes a special ability or spell tells you that you have advantage or disadvantage on an ability check, a saving throw, or an attack roll.

and the rules for initiative say:

When combat starts, every participant makes a Dexterity check to determine their place in the initiative order

Because Dexterity checks are ability checks, you can have advantage on them as you can on any other ability check.

Answer 2

Yep.

Initiative is just a Dexterity check and therefore anything that would grant you advantage or disadvantage on a Dexterity check would also carry to Initiative (unless the text would preclude its use specifically for Initiative).

Initiative At the beginning of every combat, you roll initiative by making a Dexterity check. Initiative determines the order of creatures’ turns in combat, as described in chapter 9.

The Sentinel Shield (as one example of a magical item) also grants advantage specifically to Initiative checks and since it is a d20 roll for an ability check Inspiration will also grant you advantage as well.

As Nitsua60 mentions an often overlooked condition that affects a number of things is exhaustion.

Answer 3

Yes

Anything that grants you advantage/disadvantage to Dexterity checks in general will also grant advantage/disadvantage to Initiative.

Below is a (likely incomplete) list of examples of sources of both for Dex checks, and therefore Initiative, or those that impose it on Initiative explicitly.

Sources of Advantage:

• DM Inspiration

• Enhance Ability

• Foresight

• The Help action

• Natural Explorer (Unearthed Arcana, Revised Ranger)

Sources of Disadvantage:

• Hex

• Bestow Curse

• Fear

• Resurrection (to the caster, not the target, if target has been dead > 1 year)

• Wearing armor you are not proficient with

• Frightened condition

• Exhaustion (1 level)

• Encumbrance (variant, carrying weight in excess of 10 times your Str score)

Answer 4

The PHB (pp 188) defines Initiative as:

...a Dexterity [ability] check to determine their place in the initiative order."

There are numerous ways to gain advantage/disadvantage/modifiers to Dexterity Ability Checks that range from Class features (Jack of All Trades), to Feats (Alert), to things like magical items.

It is purely a check and anything that can affect checks may affect Initiative rolls.