Ł or ł, described in English as L with stroke, is a letter of the Polish, Kashubian, Sorbian, Łacinka (Latin Belarusian), Łatynka (Latin Ukrainian), Wilamowicean, Navajo, Dene Suline, Inupiaq, Zuni, Hupa, and Dogrib alphabets, several proposed alphabets for the Venetian language, and the ISO 11940 romanization of the Thai alphabet. In Slavic languages, it represents the Lechitic–West Slavic continuation of Proto-Slavic non-palatal l (see dark L). In most non-European languages, it represents a voiceless alveolar lateral fricative or similar sound.

In Polish, Ł is used to distinguish historical dark (velarized) L from clear L.

In 1440 Jakub Parkoszowic proposed a letter resembling Failed to parse (Missing texvc executable; please see math/README to configure.): \ \ell

In modern Polish, Ł is normally pronounced /w/ (almost exactly as w in English as a consonant, as in were, will, firewall but not as in new or straw). This pronunciation first appeared among Polish lower classes in the 16th century. It was considered an uncultured accent by the upper classes (who pronounced Ł almost exactly as: л in East Slavic languages or L in English pull) until the mid-20th century when this distinction gradually began to fade. Polish final Ł also often corresponds to Ukrainian final/pre-consonant <В> (Cyrillic) and Belarusian <Ў> (Cyrillic). Thus, "he gave" is "dał" in Polish, "дав" in Ukrainian, "даў" in Belarusian, but "дал" in Russian. The old pronunciation [ɫ] of Ł is still fully understandable but is considered theatrical in most regions.