diff --git a/src/base/os.lua b/src/base/os.lua
index 759db3bff1..684ba05d5e 100644
--- a/src/base/os.lua
+++ b/src/base/os.lua
@@ -159,7 +159,16 @@
 		elseif type(headerdirs) == "table" then
 			userpaths = headerdirs
 		end
-		paths = table.join(userpaths, paths)
+
+		for _, userpath in ipairs(userpaths) do
+			if path.isabsolute(userpath) then
+				paths = table.join({userpath}, paths)
+			else
+				for _, p in ipairs(paths) do
+					paths = table.join({path.join(p, userpath)}, paths)
+				end
+			end
+		end
 
 		local result = os.pathsearch (headerpath, table.unpack(paths))
 		return result
diff --git a/tests/base/test_os.lua b/tests/base/test_os.lua
index 3900c67b54..b697ad9739 100644
--- a/tests/base/test_os.lua
+++ b/tests/base/test_os.lua
@@ -102,6 +102,15 @@
 					 os.findheader("test.h", path.getabsolute("folder/subfolder/include")))
 	end
 
+	function suite.findheader_provided_relative()
+		local os_getenv = os.getenv
+		os.getenv = create_mock_os_getenv({ [get_LD_PATH_variable_name()] = get_surrounded_env_path("folder/subfolder/lib") })
+
+		test.isequal(path.getabsolute("folder/subfolder/include/testlib"), os.findheader("testlib2.h", "testlib"))
+
+		os.getenv = os_getenv
+	end
+
 	function suite.findheader_frompath_lib()
 		local os_getenv = os.getenv
 		os.getenv = create_mock_os_getenv({ [get_LD_PATH_variable_name()] = get_surrounded_env_path("folder/subfolder/lib") })
diff --git a/tests/folder/subfolder/include/testlib/testlib2.h b/tests/folder/subfolder/include/testlib/testlib2.h
new file mode 100644
index 0000000000..a37207cc09
--- /dev/null
+++ b/tests/folder/subfolder/include/testlib/testlib2.h
@@ -0,0 +1 @@
+// Only used for presence in tests
diff --git a/website/docs/os/os.findheader.md b/website/docs/os/os.findheader.md
index dada8efa28..4e85c57131 100644
--- a/website/docs/os/os.findheader.md
+++ b/website/docs/os/os.findheader.md
@@ -6,14 +6,21 @@ p = os.findheader("headerfile" [, additionalpaths])
 
 ### Parameters ###
 
-`headerfile` is a file name or a the end of a file path to locate.
+`headerfile` is a file name of a file path to locate.
 
-`additionalpaths` is a string or a table of one or more additional search path.
+`additionalpaths` is a string or a table of one or more additional search path. The paths may be absolute or relative. If the path is a relative path, it is relative to each of the default search paths.
 
 ### Return Value ###
 
 The path containing the header file, if found. Otherwise, nil.
 
+### Example ###
+
+``` lua
+os.findheader("event.h") -- /usr/include
+os.findheader("ft2build.h", "freetype2") -- /usr/include/freetype2
+```
+
 ### Remarks ###
 `os.findheader` mostly use the same paths as [[os.findlib]] but replace `/lib` by `/include`.