diff --git a/src/lib/plugins/index.ts b/src/lib/plugins/index.ts
index 02d9b104de..9c090c7ab2 100644
--- a/src/lib/plugins/index.ts
+++ b/src/lib/plugins/index.ts
@@ -22,7 +22,7 @@ interface Options {
   docker?: boolean;
   traverseNodeModules?: boolean;
   dev?: boolean;
-  strictOutOfSync?: boolean;
+  strictOutOfSync?: boolean | 'true' | 'false';
 }
 
 interface Plugin {
diff --git a/src/lib/plugins/npm/index.ts b/src/lib/plugins/npm/index.ts
index 19cb696e85..07c5cdc7a1 100644
--- a/src/lib/plugins/npm/index.ts
+++ b/src/lib/plugins/npm/index.ts
@@ -7,7 +7,7 @@ import * as snyk from '../../';
 interface Options {
   traverseNodeModules?: boolean;
   dev?: boolean;
-  strictOutOfSync?: boolean;
+  strictOutOfSync?: boolean | 'true' | 'false';
 }
 
 interface InspectResult {
@@ -67,7 +67,7 @@ async function generateDependenciesFromLockfile(root: string, targetFile: string
   ]);
 
   const defaultManifestFileName = path.relative(root, manifestFileFullPath);
-  const strictOutOfSync = _.get(options, 'strictOutOfSync', true);
+  const strictOutOfSync = _.get(options, 'strictOutOfSync') !== 'false';
 
   return await buildDepTree(
     manifestFile,
diff --git a/src/lib/plugins/yarn/index.ts b/src/lib/plugins/yarn/index.ts
index 58f0505791..ef3b5f55b9 100644
--- a/src/lib/plugins/yarn/index.ts
+++ b/src/lib/plugins/yarn/index.ts
@@ -10,7 +10,7 @@ const debug = Debug('snyk');
 interface Options {
   traverseNodeModules?: boolean;
   dev?: boolean;
-  strictOutOfSync?: boolean;
+  strictOutOfSync?: boolean | 'true' | 'false';
 }
 
 interface InspectResult {
@@ -85,7 +85,7 @@ async function generateDependenciesFromLockfile(root, options, targetFile): Prom
   ]);
 
   const defaultManifestFileName = path.relative(root, manifestFileFullPath);
-  const strictOutOfSync = _.get(options, 'strictOutOfSync', true);
+  const strictOutOfSync = _.get(options, 'strictOutOfSync') !== 'false';
 
   return buildDepTree(
     manifestFile,
diff --git a/src/lib/snyk-test/npm/index.js b/src/lib/snyk-test/npm/index.js
index aeb904b42d..f24d982235 100644
--- a/src/lib/snyk-test/npm/index.js
+++ b/src/lib/snyk-test/npm/index.js
@@ -149,8 +149,10 @@ function generateDependenciesFromLockfile(root, options, targetFile) {
   debug(resolveModuleSpinnerLabel);
   return spinner(resolveModuleSpinnerLabel)
     .then(() => {
-      const strictOutOfSync = _.get(options, 'strictOutOfSync', true);
-      return lockFileParser.buildDepTree(manifestFile, lockFile, options.dev, lockFileType, strictOutOfSync);
+      const strictOutOfSync = _.get(options, 'strictOutOfSync') !== 'false';
+
+      return lockFileParser
+        .buildDepTree(manifestFile, lockFile, options.dev, lockFileType, strictOutOfSync);
     })
     // clear spinner in case of success or failure
     .then(spinner.clear(resolveModuleSpinnerLabel))
diff --git a/test/acceptance/cli.acceptance.test.ts b/test/acceptance/cli.acceptance.test.ts
index 24f36c1b6e..f7123c9630 100644
--- a/test/acceptance/cli.acceptance.test.ts
+++ b/test/acceptance/cli.acceptance.test.ts
@@ -867,7 +867,7 @@ if (getRuntimeVersion() > 4) {
 
   test('`test yarn-out-of-sync --strictOutOfSync=false` passes', async (t) => {
     chdirWorkspaces();
-    await cli.test('yarn-out-of-sync', { dev: true, strictOutOfSync: false});
+    await cli.test('yarn-out-of-sync', { dev: true, strictOutOfSync: 'false'});
     const req = server.popRequest();
     const pkg = req.body;
     t.equal(req.method, 'POST', 'makes POST request');
@@ -881,7 +881,7 @@ if (getRuntimeVersion() > 4) {
 
 test('`test npm-out-of-sync --strictOutOfSync=false` passes', async (t) => {
   chdirWorkspaces();
-  await cli.test('npm-out-of-sync', { dev: true, strictOutOfSync: false});
+  await cli.test('npm-out-of-sync', { dev: true, strictOutOfSync: 'false' });
   const req = server.popRequest();
   const pkg = req.body;
   t.equal(req.method, 'POST', 'makes POST request');