The W-class trams are a family of electric trams built by the Melbourne & Metropolitan Tramways Board (MMTB) between 1923 and 1956. Over the 33 years of production, 752 vehicles spanning 12 sub-classes were constructed, the majority at the MMTB's Preston Workshops.

For example, W type trams classified as W3, CW5, or SW6. Over the years many of the trams were modified and then reclassified – for example, every one of the original 200 W class trams were converted to W2 class between 1928 and 1933.

The new W-class design, first introduced in 1923, was an outstanding success, and has been the mainstay of the Melbourne tram system for the bulk of this century. It is a two-bogie, drop-centre design, which has had many variants over the years.

The W2 class of the Melbourne & Metropolitan Tramways Board (M&MTB) was the most numerous type of tramcar in Melbourne, consisting of a total of 406 trams, comprising over half of the trams built for the M&MTB. No 510 is a typical example of the W2 class.

For half a century, Melbourne’s transit system was dominated by the famed W-class trams, with a layout that reversed San Francisco’s ‘California’ design, by putting closed sections at both ends, with the lowered section for boarding and alighting placed in the middle.

This category is for W-class trams in Melbourne, for W-class trams operating outside Melbourne see: Category:Ex-Melbourne trams

The W class tram was the solution. Its drop centre provided a lower step height than the earlier straight sill (flat floor) Q class trams built by the Board. The W class tram entrances were all located in the centre of the car so the conductor could easily observe the doorways.

The W Class was the mainstay of Melbourne's tramways system for 60 years. The original and most numerous W2 variant was supplemented in the late 1930s by 120 W5 (or "Clyde") class trams with wider cabins, and more powerful motors - …

W class trams were introduced to Melbourne in 1923 as a new standard design. They had a dual bogie layout and were characterised by a substantially timber frame supplanted by a steel under frame, a simple rugged design, and fine craftsmanship (particularly the older models). The W Class was the mainstay of Melbourne's tramways system for 60 years.

The National Trust supports the retention of W Class trams to service dedicated tourism routes – giving Melbourne’s famous heritage trams a future. The key areas of focus for the National Trust’s advocacy were: Implement a moratorium on the disposal of W Class trams no longer in service