"Áo Dài" (literally "long dress") is the national dress of Vietnam, as well as the uniform for Vietnamese high school girls in certain days (like Monday, formal occasions or some holidays).. And yes, it's really form-fitting - the Vietnamese Ministry of Education is truly men of culture..

also, can we please make "ao dai" a tag on ehentai? in the meantime, I will hijack the "schoolgirl uniform" tag..

List of artists and their pixiv
Cover: ぶっくりP : https://www.pixiv.net/en/users/5094596
002-009: Nguyen Tam Lee : https://www.pixiv.net/en/users/7629816 (an artist focus on military girls in Vietnam War)
010-014: phap2000 : https://www.pixiv.net/en/users/38586207
015-023: FuyuDust : https://www.pixiv.net/en/users/39648241 (an artist focus on Vietnam topics in general)
024: Shisarou : https://www.pixiv.net/en/users/13506288
025: Acul_chan : https://www.pixiv.net/en/users/19995034
026-028: 悲しみ : https://www.pixiv.net/en/users/5148157
029: snonfield : https://www.pixiv.net/en/users/13952994
030: beNai0204 : https://www.pixiv.net/en/users/12207726
031: Xion : https://www.pixiv.net/en/users/3850071 (an artist focus on yuri and selfcest)
032-045: Hiep Studio : https://www.pixiv.net/en/users/30780986
046: 柴生かなた : https://www.pixiv.net/en/users/1452672
047: FluffyQueenz : https://www.pixiv.net/en/users/15626765
048-049: ぴちぴちデニムまつり : https://www.pixiv.net/en/users/16153560
050-053: siriuflong : https://www.pixiv.net/en/users/6414018
054-055: nannacy7 : https://www.pixiv.net/en/users/57085
056: raffijoe5 : https://www.pixiv.net/en/users/20584918
057: LVoxx : https://www.pixiv.net/en/users/30464200
058: Higeneko : https://www.pixiv.net/en/users/11396747
059-060: ba_mi : https://www.pixiv.net/en/users/38353968
061-064: なんじゃ : https://www.pixiv.net/en/users/8885157
065-066: Keaton : https://www.pixiv.net/en/users/856758
067-068: ミツキチカノ : https://www.pixiv.net/en/artworks/84043876
069: 葉月 光 : https://www.pixiv.net/en/users/11833485

Update 27/11/20
070: VonTornado : https://www.pixiv.net/en/users/28593902
071: Bainbridge : https://www.pixiv.net/en/users/321941
072-075: ばか☆黒龍 : https://www.pixiv.net/en/users/18047636
076: Ginn : https://www.pixiv.net/en/users/36947879
077: 6x2 : https://www.pixiv.net/en/users/22649431
078-079: 日暮 七十七 : https://www.pixiv.net/en/users/2283371
080: ひでつろ®️ : https://www.pixiv.net/en/users/37046432
081: sheepD : https://www.pixiv.net/en/users/14807885
082: うおぬまゆう : https://www.pixiv.net/en/users/25719
083: Coffee Bean : https://www.pixiv.net/en/users/21645058
084: 雪抹茶 : https://www.pixiv.net/en/users/14999392
085-086: とんなぐ : https://www.pixiv.net/en/users/258901
087-089: Yuriniel - 晃湧 : https://www.pixiv.net/en/users/18813645
090: きずみ : https://www.pixiv.net/en/users/34300616
091: 校長 : https://www.pixiv.net/en/users/10033894
092: あきのこと : https://www.pixiv.net/en/users/2666367
093: ねうる : https://www.pixiv.net/en/users/5774481
094: CCoordinator : https://www.pixiv.net/en/users/39505733
095: ITサラリマン : https://www.pixiv.net/en/users/45720982
096: 瓜硝子 : https://www.pixiv.net/en/users/3428600
097-098: koba（ももれぷ）: https://www.pixiv.net/en/users/8033672
099: コボリヤスヒラ : https://www.pixiv.net/en/users/20463915
100: dishwasher1910 : https://www.pixiv.net/en/users/13408193
101: Kittona : https://www.pixiv.net/en/users/1537530
102-103: urute : https://www.pixiv.net/en/users/3622
104: はとば佑 : https://www.pixiv.net/en/users/43744004
105: 御子神 : https://www.pixiv.net/en/users/5583577
106: 白水 : https://www.pixiv.net/en/users/43595048
107: なぶ : https://www.pixiv.net/en/users/276199
108: Larribee : https://www.pixiv.net/en/users/4160602
109-126 : わーうるふ03 : https://www.pixiv.net/en/users/13014433
127: FED : https://www.pixiv.net/en/users/284551
128: Cy. : https://www.pixiv.net/en/users/32791
129-130: Toba Yuga [跳馬遊鹿] : https://www.pixiv.net/en/users/1254236 - gallery HERE