So, i am planning on making a halfling character, but I hate playing short characters. Would you guys let a player play a halfling that I like 4 to 5 feet tall?

If you hate playing short characters, why are you choosing a short character?...

Generally I'd say no, because it feels like its a race that's being picked purely for the mechanics, and I prefer players to actually like the race they've picked.

4 ft, maybe, but I’m a bit of a purist on not completely derailing the printed descriptions for races.

My take on character size is that it's not hard limit, but general suggestions that represent the average race's height. I would allow a halfling to be taller than suggested. But i would likely change size to Medium if it exceeded the size limit of 4'.

Afterall, the recent tendency is to let player character select between Small or Medium size.

Size: Characters of most races are Medium, a size category including creatures that are roughly 4 to 8 feet tall. Members of a few races are Small (between 2 and 4 feet tall)

"The towering figure lumbers through the doorway, casting an impossibly long shadow across the tavern floor. 'Behold!' cries the Bard, playing an anticipatory sting on his lute, 'Titano! The world's tallest... Halfling.' The four-foot-tall fellow next to him folds his arms and glowers at the minstrel, tapping an unshod foot impatiently."

Ahem, uh, kinda depends on whether you're trying to make a halfling-in-name-only for stats' sake, or want that to be a relevant trait of the character, I guess.

I would in theory, but the change would end up with too many knock-on effects. Like how does halfling nimbleness work when you’re so big? What would it do to your walking speed. Depending on the sub-race, there may be more. 
I’d probably say you could do it, but you need to use a Tasha’s custom lineage. 

Sure, after all I’d let someone play an 8-foot human. However, you’d loose Halfling Nimbleness in exchange for a skill proficiency or two, and maybe some other changes too.

I'd probably allow it if the player really wanted to be a giant among halflings but if the character was larger than 4' tall, their size would be medium. (which I think addresses most if not all of the balance concerns).

Both Halfling Nimbleness and the Lightfoot Halfling Naturally stealthy ability specify a creature of a size larger than the halfling - so someone wanting to play a large halfling can still have these abilities but since their size will be Medium ... they will only apply to Large creatures. Which would seem to be fine to me.

Quote from David42 >>

I'd probably allow it if the player really wanted to be a giant among halflings but if the character was larger than 4' tall, their size would be medium. (which I think addresses most if not all of the balance concerns).

Both Halfling Nimbleness and the Lightfoot Halfling Naturally stealthy ability specify a creature of a size larger than the halfling - so someone wanting to play a large halfling can still have these abilities but since their size will be Medium ... they will only apply to Large creatures. Which would seem to be fine to me.

 
That’s a good point. Just making their size Medium would solve those problems.

I would have absolutely no problem with a player character having a story of having been born to a halfling and human couple. Perhaps this character then associates with their halfling upbringing and halfling culture. However, they couldn't have the Halfling Nimbleness, nor could they have any other halfling racial trait that way associated with the halfling size. Their size would also to my mind be bumped up to 'medium'.

That's how I'd do it though.

4 foot I would allow no problem with out any modifications since by definition small creatures are 2-4 feet tall. 5 foot I would allow it if it was that important to them but I would want some kind of explanation as to why they were so tall for a halfling that they incorporate in to their playing the character (maybe they have a human ancestor and have unresolved issues with that, or maybe their mother had an accident with an enlargement potion while pregnant and now have an inherent fear of all potions being something other than what they say they are, something fun like that) and I would have to say that they are now a medium size creature, for the balance issues. 

I would if they inherited some kind of giant trait. I would also give them some other traits such as stormy eyes for a storm giant or frosty hair for a frost giant.

wouldnt a tall halfling just be a normal human?? isnt them being short why they are called halflings??

also believe just because the halfling is "tall" for a halfling that it shouldnt change its size from small to medium 
what are they trying to gain by being a "tall" halfling 

dire halfling. 8ft tall!!!!

Wait, wait, I've got it, just call the character a Miniature Giant Space Halfling.

Quote from BatJamags >>

Wait, wait, I've got it, just call the character a Miniature Giant Space Halfling.

 ::::::::.....::;;;;;;;)

Wouldn't a tall halfling just be a human?

I would, but I'd stipulate a debilitating genetic illness be the reason for it, leading to a constant disadvantage in Constitution and Strength rolls, plus disadvantage on saving rolls for situations with sickening and poison.

Quote from Lambastard_13 >>

I would, but I'd stipulate a debilitating genetic illness be the reason for it, leading to a constant disadvantage in Constitution and Strength rolls, plus disadvantage on saving rolls for situations with sickening and poison.

 
Honestly, at that point you should just tell them “no” rather than essentially threatening punitive punishment for playing the character.

Quote from The_Ace_of_Rogues >>

Quote from Lambastard_13 >>

I would, but I'd stipulate a debilitating genetic illness be the reason for it, leading to a constant disadvantage in Constitution and Strength rolls, plus disadvantage on saving rolls for situations with sickening and poison.

 
Honestly, at that point you should just tell them “no” rather than essentially threatening punitive punishment for playing the character.

 And deny them the chance of finding ways to overcome it?! Perish the thought!