This is a list of languages which uses writing system to sort.

Arabic script
Arabic
Azeri (Iran)
Balochi
Berber
Bosnian (also Cyrillic script and Latin script)
Fulani (on occasion)
Hausa (on occasion)
Judaeo-Spanish (until the 20th century)
Kanuri (on occasion)
Kashmiri
Kazakh in China
Kurdish (Iran and Iraq)
Malagasy (until the 19th century)
Malay (14th - 17th century)
Mazanderani
Mozarabic (now extinct)
Ottoman Turkish
Pashtu
Persian
Punjabi (Pakistan)
Saraiki
Sindhi
Spanish (formerly before 16th century, a.k.a. Aljamiado)
Swahili (on occasion)
Tajik (on occasion)
Tausug
Urdu
Uyghur
Yoruba (rarely see Ajami script)

Many languages of Russia and Central Asia before replacement with Latin and later Cyrillic
Bashkir
Belarusian (on occasion)
Kazakh
Kyrgyz
Tatar
Uzbek

Armenian script
Armenian

Borama script
Somali

Brahmic family and derivatives

Devanagari
Sanskrit
Hindi
Marathi
Maithili
Bhojpuri
Nepali
Sindhi (also written in Arabic)
Konkani
Kashmiri
Bodo
Dogri
Gondi,Adilabad
Gondi, Aheri
Andh
Angika
Asuri
Athpariya
Awadhi
Bagheli
Bagri
Bahing
Bantawa
Baram
Bateri
Belhariya
Bhadrawahi
Bharia
Bhatri

Assamese/Bengali
Assamese
Bengali
Bishnupriya Manipuri
Garo
Kokborok
Meitei
Mundari
Sanskrit

Balinese script
Balinese language (formerly)

Baybayin script
Ilokano (formerly)
Kapampangan (formerly)
Pangasinan (formerly)
Tagalog (formerly)
Bikol language (formerly)
Visayan languages (formerly)

Buhid script
Buhid

Burmese script
Burmese
Karen
Geba Karen
Pa-O
Pwo Karen
S'gaw Karen
Mon
Rumai Palaung
Shan

Gujarati script
Gujarati

Gurmukhi script
Punjabi (also written in Shahmukhi, a variant of the Arabic script)

Hanunó'o script
Hanunó'o

Javanese script (Hanacaraka)
Javanese (in old literatures, and a part of cultural heritage)
Sundanese

Kannada script
Kannada
Konkani
Tulu

Khmer script
Khmer

Lao script
Lao

Lepcha script
Lepcha

Limbu script
Limbu

Lontara script (Buginese)
Buginese (formerly)

Malayalam script
Malayalam
Konkani

Oriya script
Oriya

'Phags-pa script
Chinese (formerly)
Mongolian (formerly)
Sanskrit (formerly)
Tibetan (for decorative purposes)
Uyghur (formerly)

Sinhala script
Sinhala

Tagbanwa script
Languages of Palawan

Tamil script
Tamil

Telugu script
Telugu

Thaana script
Dhivehi

Thai script
Thai

Tibetan script
Tibetan
Dzongkha
Ladakhi
Zhang-Zhung (extinct)

Canadian Aboriginal script
Blackfoot
Chipewyan
Cree
Dakelh
Inuktitut
Ojibwe
Sekani
Slavey
Tasttine
Tłįchǫ

Cherokee script
Cherokee

Coptic alphabet
Coptic language (extinct, still in use liturgically)

Cyrillic script

 Abkhaz
 Belarusian
 Bosnian (also Latin script and Arebica)
 Bulgarian
 Bashkir 
 Chuvash
 Dungan
 Interslavic (also Latin script)
 Judaeo-Spanish (also Latin script)
 Kazakh
 Komi
 Kyrgyz
 Macedonian
 Mongolian
 Ossetic
 Russian
 Rusyn
 Serbian (also Latin script)
 Tajiki
 Tatar
 Tuvan
 Udmurt
 Ukrainian

Bosnian Cyrillic alphabet (bosančica)
Croatian (formerly)
Bosnian (formerly)

Ge'ez script (Ethiopic)
Amharic
Ge'ez
Tigrinya

Georgian script
Georgian
Laz (sometimes Latin)
Mingrelian
Svan

Glagolitic alphabet
Old Church Slavonic (extinct, still in use liturgically)
Croatian (formerly)

Gothic alphabet
Gothic (extinct)

Greek script
Bactrian (extinct)
Greek
Gaulish (extinct) - Written in both Greek and Latin scripts
Judaeo-Spanish (also Latin script)

Chinese characters and derivatives
Chinese
Guanhua (Mandarin)
Wu which includes Shanghainese
Yue (Cantonese)
Min which includes Taiwanese
Xiang
Hakka
Gan
Jin from Mandarin
Huizhou from Wu
Ping partly from Cantonese
 Minority languages in China
Dong
Bai (obsolete)
Miao (obsolete)
Zhuang, with Zhuang logograms (obsolete)
Japanese (kanji plus kana derivative)
Korean (hanja) (obsolete; used in academic texts and newspapers)
Vietnamese (Chữ nho and Chữ nôm) (used in historic or academic texts, or for artistic or aesthetic purposes, but in general use virtually extinct)
 Extinct languages
 Khitan, written in Khitan scripts
 Jurchen, written in Jurchen script
 Tangut, written in Tangut script

Hangul
Korean

Hebrew script
Aramaic (and other writing systems)
Bukhori
Hebrew
Hulaula
Judeo-Berber
Judeo-Iraqi Arabic
Judeo-Moroccan
Judeo-Tripolitanian Arabic
Judeo-Tunisian Arabic
Judeo-Portuguese
Judeo-Spanish (originally Rashi script, and other writing systems)
Judeo-Yemenite
Juhuri
Lishan Didan
Lishana Deni
Lishanid Noshan
Shuadit
Yiddish
Zarphatic

Kaddare script
Somali

Kana
Japanese (plus kanji)
Ainu slightly modified kind of katakana kanas, which enable to represent final sounds which are consonants alone

Khitan scripts
Khitan (extinct)

Latin script
Afrikaans
Albanian
Aragonese
Asturian
Aymara
Azeri
Basque
Belarusian (formerly called "Łacinka"; now uses Cyrillic)
Bislama
Boholano (formerly used the Baybayin)
Bosnian ( also Cyrillic script and Arebica )
Breton
Catalan
Cebuano
Chamorro
Cornish
Corsican
Croatian
Czech
Danish
Dutch
English
Esperanto
Estonian
Faroese
Fijian
Filipino (formerly used the Baybayin)
Finnish
French
Frisian
Friulian
Fula (Pulaar)
Gaelic (Scottish)
Galician
Ganda
German
Gikuyu
Guaraní
Haitian
Hausa (formerly used the Arabic script)
Hawai'ian
Hiti Motu
Hungarian (used Old Hungarian script prior to AD 1000)
Icelandic
Ido
Igbo
Ilocano (formerly used the Baybayin)
Indonesian
Interlingua
Innu-aimun
Irish
Italian
Javanese - Also uses an alphabet called Hanacaraka in certain areas
Judeo-Spanish - Also uses other scripts
Kinyarwanda
Kirundi
Kongo
Kurdish (Kurmanji)
Latin
Latvian
Laz (Used by Turkey and European Lazs)
Leonese
Lingala
Lithuanian
Lombard
Luxembourgish
Maori
Malagasy
Malay
Maltese
Manx
Marshallese
Moldovan - Also Cyrillic
Montenegrin
Nahuatl (post Spanish Conquest)
Nauruan
Navaho or Navajo
Ndebele
Norwegian
Occitan
Oromo (formerly written in the Ge'ez script)
Palauan
Polish
Portuguese
Quechua
Romanian (formerly used a Cyrillic alphabet)
Romansh
Samoan
Scots
Serbian (uses Cyrillic officially)
Seychellois creole
Shona
Slovak
Slovene
Somali (formerly used the Arabic script and Osmanya script)
Sotho (Northern)
Sotho (Southern)
Spanish
Swahili
Swedish
Swati
Tagalog (formerly used the Baybayin)
Tahitian
Tatar (formerly used Arabic, 1927-1938 Latin-derived Janalif, then Cyrillic and since 2000 Latin again, but generally on the internet)
Tetum
Tok Pisin
Tongan
Tsonga
Tswana
Turkish (formerly used the Arabic script)
Turoyo (new Latin alphabet, originally Syriac alphabet)
Uzbek (official script, formerly used Cyrillic)
Venda
Vietnamese (formerly with Chữ nho and Chữ nôm)
Volapük
Võro
Walloon
Welsh
Wolof
Xhosa
Yoruba
Zulu
Zazaki

Mayan script
Mayan languages (formerly)

Mongolian and related scripts

Old Uyghur alphabet
Uyghur (formerly)

Mongolian script
Mongolian

Manchu script
Manchu
Xibe

Munda scripts

Sorang Sompeng
Sora

Ol Cemet'
Santali

Varang Kshiti
Ho

N'Ko script
N'ko

Naxi script
Naxi (obsolete)

Nsibidi
Ekoi
Igbo
Ibibio

Ogham
Primitive Irish
Pictish

Osmanya script
Somali

Pahawh Hmong
Hmong

Runic script
Proto-Norse inscriptions
Old Norse (also Latin script)
Old Danish (also Latin script)
Old English/Anglo-Saxon (also Latin script)
Old Frisian (also Latin script)

Old Hungarian script
Hungarian (also Latin script)

Syriac script
Arabic (see Garshuni)
Assyrian Neo-Aramaic
Bohtan Neo-Aramaic
Chaldean Neo-Aramaic
Hertevin
Koy Sanjaq Surat
Senaya
Syriac
Turoyo (also has new Latin-based script)

Tifinagh
Amazigh (Morocco)
Tuareg

Yi script
Yi

References

Language-related lists
Languages, list grouped by writing system