Sz is a digraph of the Latin script, used in Polish, Kashubian and Hungarian, and in the Wade–Giles system of Romanization of Mandarin, as well as the Hong Kong official romanization of Cantonese.

In Polish orthography, sz represents a voiceless retroflex fricative /ʂ/. It usually corresponds to š or ш in other Slavic languages. It is usually approximated by English speakers with the "sh" sound (and conversely, Polish speakers typically approximate the English digraph sh with the "sz" sound), although the two sounds are not completely identical.

Like other Polish digraphs, it is not considered a single letter for collation purposes.

sz should not be confused with ś (or s followed by i), termed "soft sh", a voiceless alveolo-palatal fricative /ɕ/.

obszar^ⓘ (area, territory)
płaszcz^ⓘ (coat, cloak)
Tomasz^ⓘ (Thomas)

Compare ś:
świeca^ⓘ (candle)
iść^ⓘ (to go)
sierpień^ⓘ (August)

In Kashubian, sz represents a voiceless postalveolar fricative /ʃ/, identical to the English "sh". It corresponds to the voiceless retroflex fricative /ʂ/ in Polish.

These examples are Kashubian words that use the letter sz, with the English translation following.

• szãtopiérz = bat
• szczawa = sorrel
• szczãka = jaw
• szczëka = pike (fish type)
• szerszéń = hornet

Sz is the thirty-second letter of the Hungarian alphabet. It represents /s/ and is called "esz" /ɛs/. Thus, names like Liszt are pronounced /list/ list.

In Hungarian, even if two characters are put together to make a different sound, they are considered one letter (a true digraph), and even acronyms keep the letter intact.

Hungarian usage of s and sz is almost the reverse of the Polish usage. In Hungarian, s represents /ʃ/ (a sound similar to /ʂ/). Therefore, the Hungarian capital of Budapest is natively pronounced (/ˈbudɒpɛʃt/), rhyming with standard English fleshed rather than pest.

There is also a zs in Hungarian, which is the last (forty-fourth) letter of the alphabet, following z.

These examples are Hungarian words that use the letter sz, with the English translation following:

• szabó = tailor
• szép = beautiful
• szikla = rock
• szőke = blonde
• szülő = parent
• szusi = sushi
• Olaszország = Italy
• Szudán = Sudan

In the Wade–Giles system of Romanization of Mandarin, ⟨sz⟩ is used to represent the syllabic /s/ with the "empty rime". See Wade–Giles → Empty rime.

In the unpublished romanisation scheme employed by the Hong Kong government, sz is sometimes used in combination with e to represent the syllable /siː/, as in Sheung Sze Wan /sœːŋ˥.siː˥.waːn˥/ (Sēungsīwāan in Yale romanization).

Sz also appears in the sequence tsz, representing the syllables /t͡siː/ and /t͡sʰiː/, as in Tsz Tin Tsuen /t͡siː˧˥.tʰiːn˨˩.t͡sʰyːn˥/ and Tsz Wan Shan /t͡sʰiː˨˩.wɐn˨˩.saːn˥/ (Jítìhnchyūn and Chìhwàhnsāan respectively in Yale romanization).

• Hungarian alphabet
• Polish alphabet
• ß, called S-Sharp