diff --git a/src/zona/markdown.py b/src/zona/markdown.py
index c5a83d4..1132f22 100644
--- a/src/zona/markdown.py
+++ b/src/zona/markdown.py
@@ -118,16 +118,26 @@ class ZonaLinkTreeprocessor(Treeprocessor):
                 else:
                     # treat as relative link and try to resolve
                     resolved = (self.source.parent / cur).resolve()
+                # check if the link is internal
+                internal = same_file
+                if not same_file:
+                    for suffix in {".md", ".html"}:
+                        if resolved.with_suffix(suffix).exists():
+                            internal = True
+                            resolved = resolved.with_suffix(suffix)
+                            break
                 # only substitute if link points to an actual file
                 # that isn't the self file
-                if not same_file and resolved.exists():
+                if not same_file and internal:
                     item = self.item_map.get(resolved)
                     if item:
                         href = util.normalize_url(item.url)
-                        element.set("href", href)
-                        self.logger.debug(
-                            f"Link in file {self.source}: {_href} resolved to {href}"
-                        )
+                        # don't sub if it's already correct lol
+                        if _href != href:
+                            element.set("href", href)
+                            self.logger.debug(
+                                f"Link in file {self.source}: {_href} resolved to {href}"
+                            )
                     else:
                         self.logger.debug(
                             f"Warning: resolved path {resolved} not found in item map"