diff --git a/packages/babel-core/src/transformation/normalize-opts.js b/packages/babel-core/src/transformation/normalize-opts.js
index 0b5dedffb2d7..4c53b7aa3517 100644
--- a/packages/babel-core/src/transformation/normalize-opts.js
+++ b/packages/babel-core/src/transformation/normalize-opts.js
@@ -6,7 +6,10 @@ import type { ResolvedConfig } from "../config";
 export default function normalizeOptions(config: ResolvedConfig): {} {
   const {
     filename,
-    filenameRelative = filename || "unknown",
+    cwd,
+    filenameRelative = typeof filename === "string"
+      ? path.relative(cwd, filename)
+      : "unknown",
     sourceType = "module",
     inputSourceMap,
     sourceMaps = !!inputSourceMap,
@@ -14,7 +17,7 @@ export default function normalizeOptions(config: ResolvedConfig): {} {
     moduleRoot,
     sourceRoot = moduleRoot,
 
-    sourceFileName = filenameRelative,
+    sourceFileName = path.basename(filenameRelative),
 
     comments = true,
     compact = "auto",
diff --git a/packages/babel-core/test/api.js b/packages/babel-core/test/api.js
index 0977bad100c8..621b170af4eb 100644
--- a/packages/babel-core/test/api.js
+++ b/packages/babel-core/test/api.js
@@ -394,6 +394,16 @@ describe("api", function() {
     });
   });
 
+  it("default source map filename", function() {
+    return transformAsync("var a = 10;", {
+      cwd: "/some/absolute",
+      filename: "/some/absolute/file/path.js",
+      sourceMaps: true,
+    }).then(function(result) {
+      expect(result.map.sources).toEqual(["path.js"]);
+    });
+  });
+
   it("code option false", function() {
     return transformAsync("foo('bar');", { code: false }).then(function(
       result,