diff --git a/flang/docs/FIR/CreateFIRLangRef.py b/flang/docs/FIR/CreateFIRLangRef.py
index 397163c702d7..d61671796fe8 100644
--- a/flang/docs/FIR/CreateFIRLangRef.py
+++ b/flang/docs/FIR/CreateFIRLangRef.py
@@ -1,17 +1,19 @@
 # This script combines FIRLangRef_Header.md with the auto-generated Dialect/FIRLangRef.md
-# for the purpose of creating an introduction header/paragraph for FIRLangRef.html
+# for the purpose of creating an introduction header/paragraph for FIRLangRef.html.
 
-# These paths are relative from the build directroy, not source, as that's where this tool is exectued.
-header_path = 'Source/FIR/FIRLangRef_Header.md'
-docs_path   = 'Dialect/FIRLangRef.md'
-output_path = 'Source/FIRLangRef.md'
+import os
+
+# These paths are relative to flang/docs in the build directory, not source, as that's where this tool is executed.
+HEADER_PATH = os.path.join('Source', 'FIR', 'FIRLangRef_Header.md')
+DOCS_PATH   = os.path.join('Dialect', 'FIRLangRef.md')
+OUTPUT_PATH = os.path.join('Source', 'FIRLangRef.md')
 
 # 1. Writes line 1 from docs to output, (comment line that the file is autogenerated)
 # 2. Adds a new line
 # 3. Writes the entire header to the output file
 # 4. Writes the remainder of docs to the output file
-with open(output_path, 'w') as output:
-    with open(header_path, 'r') as header, open(docs_path, 'r') as docs:
+with open(OUTPUT_PATH, 'w') as output:
+    with open(HEADER_PATH, 'r') as header, open(DOCS_PATH, 'r') as docs:
         output.write(docs.readline())
         output.write("\n")
         output.write(header.read())