diff --git a/lib/std/Io/Threaded.zig b/lib/std/Io/Threaded.zig
index 4ae5be040f3bd15e529f9f44b23c2d54ce2324a8..48a0f798cd20d89eac4c928964e80d2ff65b1953 100644
--- a/lib/std/Io/Threaded.zig
+++ b/lib/std/Io/Threaded.zig
@@ -13704,7 +13704,7 @@ fn netLookupFallible(
         // Check for equal to "localhost(.)" or ends in ".localhost(.)"
         const localhost = if (name[name.len - 1] == '.') "localhost." else "localhost";
         if (std.mem.endsWith(u8, name, localhost) and
-            (name.len == localhost.len or name[name.len - localhost.len] == '.'))
+            (name.len == localhost.len or name[name.len - localhost.len - 1] == '.'))
         {
             var results_buffer: [3]HostName.LookupResult = undefined;
             var results_index: usize = 0;