diff --git a/changelog/unreleased/kong/feat-pdk-unlimited-body-size.yml b/changelog/unreleased/kong/feat-pdk-unlimited-body-size.yml
new file mode 100644
index 000000000000..5cb3f291d15f
--- /dev/null
+++ b/changelog/unreleased/kong/feat-pdk-unlimited-body-size.yml
@@ -0,0 +1,3 @@
+message: Added `0` to support unlimited body size. When parameter `max_allowed_file_size` is `0`, `get_raw_body` will return the entire body, but the size of this body will still be limited by Nginx's `client_max_body_size`.
+type: feature
+scope: PDK
diff --git a/kong/pdk/request.lua b/kong/pdk/request.lua
index f588f06c8fb3..fbd55a741944 100644
--- a/kong/pdk/request.lua
+++ b/kong/pdk/request.lua
@@ -695,13 +695,15 @@ local function new(self)
   -- If the size of the body is greater than the Nginx buffer size (set by
   -- `client_body_buffer_size`), this function fails and returns an error
   -- message explaining this limitation, unless `max_allowed_file_size`
-  -- is set and larger than the body size buffered to disk.
+  -- is set and equal to 0 or larger than the body size buffered to disk.
   -- Use of `max_allowed_file_size` requires Kong to read data from filesystem
   -- and has performance implications.
   --
   -- @function kong.request.get_raw_body
   -- @phases rewrite, access, response, admin_api
-  -- @max_allowed_file_size[opt] number the max allowed file size to be read from
+  -- @max_allowed_file_size[opt] number the max allowed file size to be read from,
+  -- 0 means unlimited, but the size of this body will still be limited
+  -- by Nginx's client_max_body_size.
   -- @treturn string|nil The plain request body or nil if it does not fit into
   -- the NGINX temporary buffer.
   -- @treturn nil|string An error message.
@@ -721,7 +723,7 @@ local function new(self)
         return ""
       end
 
-      if not max_allowed_file_size then
+      if not max_allowed_file_size or max_allowed_file_size < 0 then
         return nil, "request body did not fit into client body buffer, consider raising 'client_body_buffer_size'"
       end
 
@@ -731,7 +733,7 @@ local function new(self)
       end
 
       local size = file:seek("end") or 0
-      if size > max_allowed_file_size then
+      if max_allowed_file_size > 0 and size > max_allowed_file_size then
         return nil, ("request body file too big: %d > %d"):format(size, max_allowed_file_size)
       end
 
diff --git a/t/01-pdk/04-request/15-get_raw_body.t b/t/01-pdk/04-request/15-get_raw_body.t
index 490354ac7408..2e47aeb461da 100644
--- a/t/01-pdk/04-request/15-get_raw_body.t
+++ b/t/01-pdk/04-request/15-get_raw_body.t
@@ -170,4 +170,30 @@ body length: 20000
 --- response_body
 body err: request body file too big: 20000 > 19999
 --- no_error_log
-[error]
\ No newline at end of file
+[error]
+
+
+
+=== TEST 8: request.get_raw_body() returns correctly if max_allowed_file_size is equal to 0
+--- http_config eval: $t::Util::HttpConfig
+--- config
+    location = /t {
+        access_by_lua_block {
+            local PDK = require "kong.pdk"
+            local pdk = PDK.new()
+
+            local body, err = pdk.request.get_raw_body(0)
+            if body then
+              ngx.say("body length: ", #body)
+
+            else
+              ngx.say("body err: ", err)
+            end
+        }
+    }
+--- request eval
+"GET /t\r\n" . ("a" x 20000)
+--- response_body
+body length: 20000
+--- no_error_log
+[error]