diff --git a/src/libutil/file-system.cc b/src/libutil/file-system.cc
index 9dd6a5133..fc0f216ea 100644
--- a/src/libutil/file-system.cc
+++ b/src/libutil/file-system.cc
@@ -128,7 +128,7 @@ std::string_view baseNameOf(std::string_view path)
         return "";
 
     auto last = path.size() - 1;
-    if (path[last] == '/' && last > 0)
+    while (last > 0 && path[last] == '/')
         last -= 1;
 
     auto pos = path.rfind('/', last);
diff --git a/tests/unit/libutil/tests.cc b/tests/unit/libutil/tests.cc
index 4406fd184..d7e9edf0a 100644
--- a/tests/unit/libutil/tests.cc
+++ b/tests/unit/libutil/tests.cc
@@ -151,6 +151,16 @@ namespace nix {
         ASSERT_EQ(p1, "dir");
     }
 
+    TEST(baseNameOf, trailingSlashes) {
+        auto p1 = baseNameOf("/dir//");
+        ASSERT_EQ(p1, "dir");
+    }
+
+    TEST(baseNameOf, absoluteNothingSlashNothing) {
+        auto p1 = baseNameOf("//");
+        ASSERT_EQ(p1, "");
+    }
+
     /* ----------------------------------------------------------------------------
      * isInDir
      * --------------------------------------------------------------------------*/