diff --git a/lib/object.js b/lib/object.js
index cd36d0c..d42b6e0 100644
--- a/lib/object.js
+++ b/lib/object.js
@@ -279,7 +279,7 @@ function sortFields(fields) {
         if (! ~excludes.indexOf(key + '-' + node)) edges.push([key, node]);
       };
 
-      if (Ref.isRef(value) && !value.isContext) addNode(value.path);else if (isSchema(value)) value._deps.forEach(addNode);
+      if (Ref.isRef(value) && !value.isContext) addNode(value.path);else if (isSchema(value) && value._deps) value._deps.forEach(addNode);
     }
   }return toposort.array(nodes, edges).reverse();
 }
\ No newline at end of file
diff --git a/lib/util/lazy.js b/lib/util/lazy.js
index 0025480..bd7515d 100644
--- a/lib/util/lazy.js
+++ b/lib/util/lazy.js
@@ -41,5 +41,7 @@ var Lazy = function () {
   return Lazy;
 }();
 
+Lazy.prototype.__isYupSchema__ = true;
+
 exports.default = Lazy;
 module.exports = exports['default'];
\ No newline at end of file
diff --git a/src/object.js b/src/object.js
index 85af273..a1ebfbf 100644
--- a/src/object.js
+++ b/src/object.js
@@ -85,7 +85,7 @@ inherits(ObjectSchema, MixedSchema, {
       , extra  = Object.keys(value).filter(v => this._nodes.indexOf(v) === -1)
       , props  = this._nodes.concat(extra);
 
-    let innerOptions = { ...opts, parent: {} };
+    let innerOptions = { ...opts, parent: {}, __validating: false };
 
     value = transform(props, function(obj, prop) {
       let field = fields[prop]
@@ -94,10 +94,14 @@ inherits(ObjectSchema, MixedSchema, {
       if (field) {
         let fieldValue;
 
+        let strict = field._options && field._options.strict;
+
         if (field._strip === true)
           return
 
-        fieldValue = field.cast(value[prop], innerOptions)
+        fieldValue = !opts.__validating || !strict
+          ? field.cast(value[prop], innerOptions)
+          : value[prop]
 
         if (fieldValue !== undefined)
           obj[prop] = fieldValue
@@ -117,6 +121,8 @@ inherits(ObjectSchema, MixedSchema, {
     endEarly = this._option('abortEarly', opts)
     recursive = this._option('recursive', opts)
 
+    opts = {...opts, __validating: true };
+
     return MixedSchema.prototype._validate
       .call(this, _value, opts)
       .catch(endEarly ? null : err => {
diff --git a/test/object.js b/test/object.js
index 97966be..c72686f 100644
--- a/test/object.js
+++ b/test/object.js
@@ -122,6 +122,18 @@ describe('Object types', function(){
       err.message.should.match(/must be a `string` type/)
     })
 
+    it ('should respect child schema with strict()', async () => {
+      inst = object({
+        field: number().strict()
+      })
+
+      let err = await inst.validate({ field: '5' }).should.be.rejected
+
+      err.message.should.match(/must be a `number` type/)
+
+      inst.cast({ field: '5' }).should.eql({ field: 5 })
+    })
+
     it('should handle custom validation', async function(){
       var inst = object().shape({
         prop: mixed(),