Legnanese dialect (native name legnanés, IPA: [leɲaˈneːs]) is a dialect of the Lombard language (belonging to the western branch) that is spoken around Legnano, a municipality in the metropolitan city of Milan, Lombardy. It is spoken by about 30 percent of the population of the area in which it is spread.

Legnano, starting in the 11th century, began to bond with Milan. The village of Legnano represented, for those coming from the north, the gateway to the Milanese countryside and thus had an important strategic function for the city of Milan. The link between Legnano and Milan also influenced the Legnano vernacular, which began to differentiate itself from the neighboring Bustocco dialect. Due to the frequent contacts between the two cities, the Milanese dialect began to "contaminate" the dialect spoken in Legnano. Despite this trend, the Legnano dialect continued to preserve - over the centuries - a considerable difference from the Milanese dialect.

An important distinctive phonetic trait that is present in Legnanese and neighboring Bustocco, and that differentiates these dialects from the idioms of contiguous isoglosses, is the preservation of unaccented final vowels. However, due to the contamination of the Milanese dialect, the Legnano vernacular, unlike the Bustocco dialect, does not preserve the final atonal vowel for many words. Another feature that differentiates the Legnano dialect from the Bustocco dialect concerns the intervocalic -r. In the Legnanese vernacular it has been preserved, while in the Bustocco vernacular it has been eliminated.

The plays of the Italian dialect theater company "I Legnanesi" are written in the Legnanese dialect.

The oldest linguistic substratum that has left a trace in Legnanese and of which there are some records is that of the ancient Ligurians. However, the information available for this idiom is very vague and extremely limited. The picture that can be drawn for the populations that replaced the Ligurians, the Celts (or "Gauls"), is quite different. The linguistic influence of the Celts on the local language was striking, so much so that even today the dialect of Legnano is classified as "Gallo-Roman". However, it was the Roman domination, which replaced the Celtic one, that shaped the local language spoken in Legnano, so much so that the lexicon and the grammar of this language are of Romance derivation.

However, the influence of the Latin language in the dominated territories was not homogeneous. The idioms spoken in the different areas were in fact influenced by the earlier linguistic substrata. Each area was characterized by a greater or lesser characterization towards ancient Ligurian or Celtic languages, and Legnanese was no exception. However, data on the real influence of these two substrates on the various dialects are very scarce and of different interpretation. This has given rise to a debate among linguists that has led to great caution in attributing a given phonetic feature of the Legnanese dialect to the Ligurian or Celtic substratum.

The birth of modern Italian dialects can be traced back to the situation after the fall of the Western Roman Empire. The local population suffered an administrative, economic, demographic and cultural regression that led to the formation of small communities isolated from each other. Because of the isolation suffered by these groups, the language spoken evolved into different variants that were characteristic of the community that used them. The linguistic boundaries of these dialects were then defined in later centuries with the establishment of parishes. These parishes were, in fact, the reference point of a particular community, which gathered around them to discuss and solve everyday problems. As a result, each parish had its own isogloss, whose linguistic boundaries have survived, with minor modifications, until the 21st century.

Legnano, from the 11th century, began to connect with Milan. The town of Legnano, in fact, represented an easy access to the Milanese countryside for those coming from the north, since it was located at the outlet of the Olona Valley, which ends in Castellanza; such a gateway therefore had to be closed and strongly defended to prevent an attack on Milan, which was also facilitated by the presence of an important road that had existed since Roman times, the Via Severiana Augusta, which connected Mediolanum (modern Milan) with the Verbannus Lacus (Lake Verbano, i.e., Lake Maggiore). Its route was later taken over by Napoleon Bonaparte to build the Simplon highway.