Should the monk get to add their ability modifier to the damage on a bonus attack unarmed strike if the main attack is a monk weapon, since now they are hitting with the offhand like in Two-weapon fighting? The D&D Beyond character sheet indicates either either monk weapon or unarmed strike bonus action unarmed strike gets the ability modifier damage added which does conflict directly with the Two-Weapon Fighting rules for damage application in which the bonus attack does not apply ability modifiers to damage on the offhand weapon.

Or is the ability modifier only applied to the bonus action unarmed strike if the first strike is also unarmed since this wouldn’t technically have to be two-weapon fighting if made with the same hand

Hello there CooperS,

I think you will find that this is a case of the monk’s unarmed strike being treated differently to two weapon fighting. Two weapon fighting specifies

When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand. You don't add your ability modifier to the damage of the bonus attack, unless that modifier is negative.

While the unarmed strike rule says

• When you use the Attack action with an unarmed strike or a monk weapon on your turn, you can make one unarmed strike as a bonus action. For example, if you take the Attack action and attack with a quarterstaff, you can also make an unarmed strike as a bonus action, assuming you haven’t already taken a bonus action this turn.

Essentially, a monk’s unarmed strike is not two weapon fighting.

When attacking with a weapon, you always add your ability modifier—the same modifier used for the Attack roll—to the damage.  Unless there is a specific rule that says not to. "Two-Weapon Fighting" is a specific rule regarding the bonus action attack you can make when attacking with two weapons. If you meet the criteria for it (two weapons, both light, etc). Think of it as a light quick (and thus less powerful) attack you can make with you offhand as a bonus action on top of your regular attack action.

Monk using its martial arts feature to attack with its unarmed strike as a bonus action is a different thing. Same as a combatant can attack with two weapons with the attack acton using its extra attack feature and still apply the damage modifier. Its the bonus action attack you make with Two Weapon Fighting that doesn't get the bonus damage as per the specific rule. 

1)Therefor could a Monk Attack with an unarmed attack as the ATTACK and an unarmed attack as the BONUS with all the same modifiers?

2)  Under the "two weapon fighting" if the Monk used a handaxe for the ATTACK and another handaxe for the BONUS they would only get the Proficiency modifier, Correct?

Whenever you make a attack, you add Prof + Mod to hit and only Mod to damage.

Two weapon fighting makes a exception that when you attack with one light weapon, and make a bonus action attack with another, you add nothing to damage.

Monk attacks does not have that exception, and thus you add Mod to damage because nothing says otherwise.

Quote from TheGrayShade >>

1)Therefor could a Monk Attack with an unarmed attack as the ATTACK and an unarmed attack as the BONUS with all the same modifiers?

2)  Under the "two weapon fighting" if the Monk used a handaxe for the ATTACK and another handaxe for the BONUS they would only get the Proficiency modifier, Correct?

 1. Yes. If the Attack action is used to make a monk weapon attack or unarmed strike you can bonus action unarmed strike with modifiers. Martial arts is not two weapon fighting. So Proficiency mod + ability mod to hit, and ability mod to damage both attacks 

2. a hand axe As BA is not an unarmed strike so would fall under TWF and no ability mod to damage 

I get what everyone is saying, but two weapon fighting off hand weapon and the monk extra attack are the same exact scenario except the extra attack for the monk is based on the first attack hitting in order to use the bonus attack. Why is the monk considered essentially stronger or more dexterous than a two weapon fighter by getting to add the ability modifier when a two-weapon fighter can’t. Basically the monk is getting favoritism here.

I can let it go because that is how the rules read. I just feel it’s disparate in it’s treatment of the monk and other fighting classes and wanted to see what others takes were.

Thanks for confirming my understanding.

Quote from CooperS >>

I get what everyone is saying, but two weapon fighting off hand weapon and the monk extra attack are the same exact scenario except the extra attack for the monk is based on the first attack hitting in order to use the bonus attack. Why is the monk considered essentially stronger or more dexterous than a two weapon fighter by getting to add the ability modifier when a two-weapon fighter can’t. Basically the monk is getting favoritism here.

I can let it go because that is how the rules read. I just feel it’s disparate in it’s treatment of the monk and other fighting classes and wanted to see what others takes were.

Thanks for confirming my understanding.

 A Fighter can take the 2 weapon fighting style and get the bonus damage to off hand attack, the monk has to do an unarmed attack which means the martial arts die they have earned.

  I do not think it is disparate in its treatment of monks.  The 2 weapon fighting is something anyone can do and if you have the feat then you can add the damage modifier.  If you compare the damage an average Fighter does to that of a monk the fighter is doing more damage.  I also think it fits with the Monk idea that through their training they can hit multiple times with their hands.  The weapon and a hand always seemed a little off to me.        With my original question I was just trying to clear up which modifiers applied.

CooperS:  Are you saying a 2 weapon attack AND an unarmed attack??  I do not understand that to be possible.

p.s.  Thank-you ThriKreenWarrior for being more clear with your answer to my question.

Quote from CooperS >>

I get what everyone is saying, but two weapon fighting off hand weapon and the monk extra attack are the same exact scenario except the extra attack for the monk is based on the first attack hitting in order to use the bonus attack. Why is the monk considered essentially stronger or more dexterous than a two weapon fighter by getting to add the ability modifier when a two-weapon fighter can’t. Basically the monk is getting favoritism here.

It’s not the exact same scenario. The monk can only do this if using a monk weapon, and the bonus action attack is only one of three ways the Martial Arts monk ability differentiates between what a monk can do with these weapons and what non-monks can. Non-monks can use whatever two-weapon fighting abilities they have while armored, monks can’t. The Dual Wielder feat’s benefit with regards to non-light weapons is largely useless to monks. A Champion Fighter can add the Defense fighting style to TWF and benefits from Improved Critical on all his attacks (bonus action attacks included). Most of. Battle Master’s maneuvers can be performed as part of a bonus action attack. Paladins can smite through bonus action attacks. Rogues can apply Sneak Attack damage to a bonus action attack, assuming they haven’t already used that ability on another attack that turn. An Assassin Rogue’s Death Strike applies to bonus action attacks.

Different classes have different qualities. That’s not favoritism, it’s making them distinct by design.

Quote from TheGrayShade > 

CooperS:  Are you saying a 2 weapon attack AND an unarmed attack??  I do not understand that to be possible.

 nope. 

I understand the differences. I just think it’s too similar and should follow the same rules for off hand damage. The monk in my party will be VERY happy to here the results of this thread.

Thanks everyone!

Quote from CooperS >>

Quote from TheGrayShade > 

CooperS:  Are you saying a 2 weapon attack AND an unarmed attack??  I do not understand that to be possible.

 nope. 

I understand the differences. I just think it’s too similar and should follow the same rules for off hand damage. The monk in my party will be VERY happy to here the results of this thread.

Thanks everyone!

 The thing is, it isn't an "Off hand" attack. It is a bonus action attack. So if you take the attack action and punch someone in the face you can use your bonus action to punch them in the face again (or kick them, or headbutt them, or elbow them, etc...) You do not have to use two different weapons to do this so there is no "Off hand", it can literally be the same exact hand you hit them with in the first place. Technically an unarmed strike is not even a weapon, though for monks it does qualify with being a "melee weapon attack", but not an "attack with a melee weapon", I think, so it qualifies for Stunning Strike.