This is a list of Douglas motorcycles please add to it or update where you can:
| Model | Engine | Years | Notes |
| Douglas 350cc | 350 cc | 1910 | |
| Douglas 349cc | 349 cc | 1914–1918 | Developed primarily for use as a dispatch motorcycle. Also referred to as the 2¾HP (two and three quarter horsepower) |
| Douglas 596cc | 596cc side-valve | 1915-1924 | Developed for use w sidecar during World War I. Also known as the 4HP (four horsepower)
 |
| TS 250cc | 250 cc | 1915 | |
| CW | 1924 | ||
| EW | 350cc | 1926 | |
| E/28 | 600 cc side-valve | 1928 | |
| A/29 | 350 cc | 1929 | |
| B/29 | 350 cc | 1929 | OHV Sports |
| D/29 | 350 cc | 1929 | Touring & Competition |
| E/29 | 600 cc side-valve | 1929 | |
| F/29 | 600 cc side-valve | 1929 | Sports edition of E/29 |
| G/29 | 600 cc | 1929 | OHV engine |
| H/29 | 600 cc | 1929 | OHV Sports Model |
| Dirt Track Model | 500 cc | 1929 | |
| T.T. Model | 350 cc or 500 cc | 1929 | High speed competition bike |
| FW 500 | 500/600 cc | 1929 | |
| S5 | 500 cc | 1930 | |
| S6 | 600 cc | 1930 | |
| T6 | 600 cc | 1930 | |
| A.32 | 350 cc side-valve | 1932 | |
| B.32 | 350 cc side-valve | 1932 | Touring |
| C.32 | 500 cc side-valve | 1932 | |
| D.32 | 600 cc side-valve | 1932 | Greyhound Touring |
| E.32 | 600 cc side-valve | 1932 | |
| F.32 | 500 cc ohv | 1932 | Sports |
| G.32 | 600 cc ohv | 1932 | Sports |
| H.32 | 750 cc side-valve | 1932 | |
| K.32 | 350 cc ohv | 1932 | Touring |
| M.32 | 350 cc ohv | 1932 | Touring |
| S.W.5 | 500 cc ohv | 1932 | Speed |
| S.W.6 | 600 cc ohv | 1932 | Speed |
| D.T.5 | 500 cc ohv | 1932 | Dirt Track |
| D.T.6 | 600 cc ohv | 1932 | Dirt Track |
| SV | 600 cc | 1937 | DeLuxe Twin |
| DC38 | 600cc (594cc) | 1938 | twin |
| T35 | 350 cc | 1945 | |
| Mark III | 350 cc | 1949 | |
| Mark III De Luxe | 350 cc | 1949 | |
| Mark III Competition | 350 cc | 1949 | |
| Mark III Sports | 350 cc | 1948 | |
| Douglas "Vespa" | 1950 | ||
| Mark V | 350 cc | 1951 | |
| Douglas Dragonfly | 348 cc horizontally opposed twin-cylinder four-stroke | 1955–1957 | 1,457 Dragonfly motorcycles were produced before the company was taken over and production ended in 1957. |
