Marlin Model 20

{{More citations needed|date=June 2025}}

{{Infobox weapon

| image = Marlin model 20 1.JPG

| image_size = 300

| caption =

| name = Marlin Glenfield Model 20

| origin = United States

| type = Hunting rifle

| is_ranged = yes

| designer = Marlin Firearms

| design_date = 1960

| cartridge = .22LR, .22 Short, .22 Long

| action = Bolt-action

| range = 100 yards

| weight = 5 lb (2 kg)

| length = 41 in (1,040 mm)

| part_length = 21 in (530 mm)

| feed = 7 rounds; box magazine

| sights = adjustable open rear, ramp front sight; receiver is grooved for a scope mount|

}}

The Marlin No. 20 is a slide-action .22 caliber rifle with an octagonal barrel and tubular magazine, bearing patents of August 12, 1890 through November 29, 1904, produced by the Marlin Firearms Co. of New Haven, Connecticut.{{Cite book |last=Brophy |first=William S |url=https://books.google.com/books?id=G50qAAAACAAJ |title=Marlin Firearms: A History of the Guns and the Company That Made Them |publisher=Stackpole Books |year=1989 |isbn=9780811708777 |location=Harrisburg, Pennsylvania |publication-date=1989 |pages=444 |language=en}}

It is not the same as the Glenfield Model 20 (Marlin 780). The Model 20 is a bolt-action rifle that fires primarily the .22LR rimfire cartridge, but also the .22 short, and the obsolete .22 long (all rimfire cartridges, and can all be fired in the same gun). Produced by the Marlin Firearms Company of North Haven, Connecticut, it was in production from 1960 to 1966.