diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3dd8948a..9837cce8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@ Change Log
 
 v5.4.7
 ---
+* Fixed directory obfuscation with a set `sourceMapFileName` making all files share and overwrite one `.map`. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/817
 * Fixed CLI `--config` failures hiding the real cause behind a generic `Cannot open config file` message. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1101
 * Fixed `sourceMapFileName` ending in `.js.map` (e.g. `foo.min.js.map`) being mangled in the emitted `//# sourceMappingURL=` comment. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1312
 * Fixed `URIError: URI malformed` crash when `stringArray` with `base64`/`rc4` encoding processed a string literal containing lone surrogate code units (e.g. `"[^\uD800-\uDFFF]"`). Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1431
diff --git a/src/cli/utils/ObfuscatedCodeFileUtils.ts b/src/cli/utils/ObfuscatedCodeFileUtils.ts
index 443f225d..1f421362 100644
--- a/src/cli/utils/ObfuscatedCodeFileUtils.ts
+++ b/src/cli/utils/ObfuscatedCodeFileUtils.ts
@@ -88,6 +88,8 @@ export class ObfuscatedCodeFileUtils {
             throw new Error('Output code path is empty');
         }
 
+        sourceMapFileName = this.getUniqueSourceMapFileName(outputCodePath, sourceMapFileName);
+
         let normalizedOutputCodePath: string = path.normalize(outputCodePath);
         let parsedOutputCodePath: path.ParsedPath = path.parse(normalizedOutputCodePath);
 
@@ -140,4 +142,37 @@ export class ObfuscatedCodeFileUtils {
             encoding: JavaScriptObfuscatorCLI.encoding
         });
     }
+
+    /**
+     * For directory obfuscation a single `sourceMapFileName` would be shared by every file and the
+     * source maps would overwrite each other, so it is prefixed with the output code file name to
+     * keep each source map unique.
+     * https://github.com/javascript-obfuscator/javascript-obfuscator/issues/817
+     *
+     * @param {string} outputCodePath
+     * @param {string} sourceMapFileName
+     * @returns {string}
+     */
+    private getUniqueSourceMapFileName(outputCodePath: string, sourceMapFileName: string): string {
+        if (!sourceMapFileName || !this.isDirectoryInputPath()) {
+            return sourceMapFileName;
+        }
+
+        const outputCodeName: string = path.parse(outputCodePath).name;
+        const parsedSourceMapFileName: path.ParsedPath = path.parse(sourceMapFileName);
+
+        // keep any leading directory part of `sourceMapFileName`, prefix only its file name
+        return path.join(parsedSourceMapFileName.dir, `${outputCodeName}-${parsedSourceMapFileName.base}`);
+    }
+
+    /**
+     * @returns {boolean}
+     */
+    private isDirectoryInputPath(): boolean {
+        try {
+            return fs.lstatSync(this.inputPath).isDirectory();
+        } catch {
+            return false;
+        }
+    }
 }
diff --git a/test/unit-tests/cli/utils/ObfuscatedCodeFileUtils.spec.ts b/test/unit-tests/cli/utils/ObfuscatedCodeFileUtils.spec.ts
index db0fac26..14672dc8 100644
--- a/test/unit-tests/cli/utils/ObfuscatedCodeFileUtils.spec.ts
+++ b/test/unit-tests/cli/utils/ObfuscatedCodeFileUtils.spec.ts
@@ -715,6 +715,49 @@ describe('obfuscatedCodeFileUtils', () => {
             });
         });
 
+        // https://github.com/javascript-obfuscator/javascript-obfuscator/issues/817
+        describe('Variant #2: input path is a directory', () => {
+            const rawInputPath: string = path.join(tmpDirectoryPath, 'sm-input');
+            const rawOutputPath: string = path.join(tmpDirectoryPath, 'output');
+            const sourceMapFileName: string = 'map';
+
+            let firstOutputSourceMapPath: string;
+            let secondOutputSourceMapPath: string;
+
+            before(() => {
+                fs.mkdirSync(rawInputPath, { recursive: true });
+
+                const obfuscatedCodeFileUtils: ObfuscatedCodeFileUtils = new ObfuscatedCodeFileUtils(rawInputPath, {
+                    output: rawOutputPath
+                });
+
+                firstOutputSourceMapPath = obfuscatedCodeFileUtils.getOutputSourceMapPath(
+                    path.join(rawOutputPath, 'foo.js'),
+                    sourceMapFileName
+                );
+                secondOutputSourceMapPath = obfuscatedCodeFileUtils.getOutputSourceMapPath(
+                    path.join(rawOutputPath, 'bar.js'),
+                    sourceMapFileName
+                );
+            });
+
+            after(() => {
+                rimraf.sync(rawInputPath);
+            });
+
+            it('match #1: should prefix the source map file name with the output code file name', () => {
+                assert.equal(firstOutputSourceMapPath, path.join(rawOutputPath, 'foo-map.js.map'));
+            });
+
+            it('match #2: should prefix the source map file name with the output code file name', () => {
+                assert.equal(secondOutputSourceMapPath, path.join(rawOutputPath, 'bar-map.js.map'));
+            });
+
+            it('should produce a unique source map path per file', () => {
+                assert.notEqual(firstOutputSourceMapPath, secondOutputSourceMapPath);
+            });
+        });
+
         describe('Variant #3: empty paths', () => {
             const rawInputPath: string = path.join(tmpDirectoryPath, 'input', 'test-input.js');
             const rawOutputPath: string = path.join(tmpDirectoryPath, 'output', 'test-output.js');