diff --git a/packages/forms/src/validators.ts b/packages/forms/src/validators.ts
index a1e8f8a157..ab09fa6f08 100644
--- a/packages/forms/src/validators.ts
+++ b/packages/forms/src/validators.ts
@@ -11,13 +11,18 @@ import {forkJoin, from, Observable} from 'rxjs';
 import {map} from 'rxjs/operators';
 
 import {AsyncValidatorFn, ValidationErrors, Validator, ValidatorFn} from './directives/validators';
-import {AbstractControl, FormControl} from './model';
+import {AbstractControl} from './model';
 
 function isEmptyInputValue(value: any): boolean {
   // we don't check for string here so it also works with arrays
   return value == null || value.length === 0;
 }
 
+function hasValidLength(value: any): boolean {
+  // non-strict comparison is intentional, to check for both `null` and `undefined` values
+  return value != null && typeof value.length === 'number';
+}
+
 /**
  * @description
  * An `InjectionToken` for registering additional synchronous validators used with
@@ -295,12 +300,14 @@ export class Validators {
    */
   static minLength(minLength: number): ValidatorFn {
     return (control: AbstractControl): ValidationErrors|null => {
-      if (isEmptyInputValue(control.value)) {
-        return null;  // don't validate empty values to allow optional controls
+      if (isEmptyInputValue(control.value) || !hasValidLength(control.value)) {
+        // don't validate empty values to allow optional controls
+        // don't validate values without `length` property
+        return null;
       }
-      const length: number = control.value ? control.value.length : 0;
-      return length < minLength ?
-          {'minlength': {'requiredLength': minLength, 'actualLength': length}} :
+
+      return control.value.length < minLength ?
+          {'minlength': {'requiredLength': minLength, 'actualLength': control.value.length}} :
           null;
     };
   }
@@ -334,9 +341,8 @@ export class Validators {
    */
   static maxLength(maxLength: number): ValidatorFn {
     return (control: AbstractControl): ValidationErrors|null => {
-      const length: number = control.value ? control.value.length : 0;
-      return length > maxLength ?
-          {'maxlength': {'requiredLength': maxLength, 'actualLength': length}} :
+      return hasValidLength(control.value) && control.value.length > maxLength ?
+          {'maxlength': {'requiredLength': maxLength, 'actualLength': control.value.length}} :
           null;
     };
   }
diff --git a/packages/forms/test/validators_spec.ts b/packages/forms/test/validators_spec.ts
index 0a6719421b..8cbbf223bf 100644
--- a/packages/forms/test/validators_spec.ts
+++ b/packages/forms/test/validators_spec.ts
@@ -225,6 +225,26 @@ describe('Validators', () => {
         'minlength': {'requiredLength': 2, 'actualLength': 1}
       });
     });
+
+    it('should always return null with numeric values', () => {
+      expect(Validators.minLength(1)(new FormControl(0))).toBeNull();
+      expect(Validators.minLength(1)(new FormControl(1))).toBeNull();
+      expect(Validators.minLength(1)(new FormControl(-1))).toBeNull();
+      expect(Validators.minLength(1)(new FormControl(+1))).toBeNull();
+    });
+
+    it('should trigger validation for an object that contains numeric length property', () => {
+      const value = {length: 5, someValue: [1, 2, 3, 4, 5]};
+      expect(Validators.minLength(1)(new FormControl(value))).toBeNull();
+      expect(Validators.minLength(10)(new FormControl(value))).toEqual({
+        'minlength': {'requiredLength': 10, 'actualLength': 5}
+      });
+    });
+
+    it('should return null when passing a boolean', () => {
+      expect(Validators.minLength(1)(new FormControl(true))).toBeNull();
+      expect(Validators.minLength(1)(new FormControl(false))).toBeNull();
+    });
   });
 
   describe('maxLength', () => {
@@ -261,6 +281,26 @@ describe('Validators', () => {
         'maxlength': {'requiredLength': 1, 'actualLength': 2}
       });
     });
+
+    it('should always return null with numeric values', () => {
+      expect(Validators.maxLength(1)(new FormControl(0))).toBeNull();
+      expect(Validators.maxLength(1)(new FormControl(1))).toBeNull();
+      expect(Validators.maxLength(1)(new FormControl(-1))).toBeNull();
+      expect(Validators.maxLength(1)(new FormControl(+1))).toBeNull();
+    });
+
+    it('should trigger validation for an object that contains numeric length property', () => {
+      const value = {length: 5, someValue: [1, 2, 3, 4, 5]};
+      expect(Validators.maxLength(10)(new FormControl(value))).toBeNull();
+      expect(Validators.maxLength(1)(new FormControl(value))).toEqual({
+        'maxlength': {'requiredLength': 1, 'actualLength': 5}
+      });
+    });
+
+    it('should return null when passing a boolean', () => {
+      expect(Validators.maxLength(1)(new FormControl(true))).toBeNull();
+      expect(Validators.maxLength(1)(new FormControl(false))).toBeNull();
+    });
   });
 
   describe('pattern', () => {