diff --git a/modules/dnn/src/layers/prior_box_layer.cpp b/modules/dnn/src/layers/prior_box_layer.cpp
index 0756f38f80..1e41585672 100644
--- a/modules/dnn/src/layers/prior_box_layer.cpp
+++ b/modules/dnn/src/layers/prior_box_layer.cpp
@@ -369,15 +369,11 @@ public:
         // clip the prior's coordinate such that it is within [0, 1]
         if (_clip)
         {
-            Mat mat = outputs[0].getMat(ACCESS_READ);
-            int aspect_count = (_maxSize > 0) ? 1 : 0;
-            int offset = nthreads * 4 * _offsetsX.size() * (1 + aspect_count + _aspectRatios.size());
-            float* outputPtr = mat.ptr<float>() + offset;
-            int _outChannelSize = _layerHeight * _layerWidth * _numPriors * 4;
-            for (size_t d = 0; d < _outChannelSize; ++d)
-            {
-                outputPtr[d] = std::min<float>(std::max<float>(outputPtr[d], 0.), 1.);
-            }
+            ocl::Kernel kernel("clip", ocl::dnn::prior_box_oclsrc, opts);
+            size_t nthreads = _layerHeight * _layerWidth * _numPriors * 4;
+            if (!kernel.args((int)nthreads, ocl::KernelArg::PtrReadWrite(outputs[0]))
+                       .run(1, &nthreads, NULL, false))
+                return false;
         }
 
         // set the variance.
diff --git a/modules/dnn/src/opencl/prior_box.cl b/modules/dnn/src/opencl/prior_box.cl
index 6ffbf8df29..d898a13ffd 100644
--- a/modules/dnn/src/opencl/prior_box.cl
+++ b/modules/dnn/src/opencl/prior_box.cl
@@ -107,3 +107,13 @@ __kernel void set_variance(const int nthreads,
         vstore4(var_vec, 0, dst + offset + index * 4);
     }
 }
+
+__kernel void clip(const int nthreads,
+                   __global Dtype* dst)
+{
+    for (int index = get_global_id(0); index < nthreads; index += get_global_size(0))
+    {
+        Dtype4 vec = vload4(index, dst);
+        vstore4(clamp(vec, 0, 1), index, dst);
+    }
+}
diff --git a/modules/dnn/test/test_layers.cpp b/modules/dnn/test/test_layers.cpp
index bd567ce72e..ca6645057b 100644
--- a/modules/dnn/test/test_layers.cpp
+++ b/modules/dnn/test/test_layers.cpp
@@ -763,8 +763,7 @@ TEST_P(Test_Caffe_layers, Average_pooling_kernel_area)
 // Test PriorBoxLayer in case of no aspect ratios (just squared proposals).
 TEST_P(Test_Caffe_layers, PriorBox_squares)
 {
-    if (backend == DNN_BACKEND_INFERENCE_ENGINE ||
-        (backend == DNN_BACKEND_OPENCV && (target == DNN_TARGET_OPENCL || target == DNN_TARGET_OPENCL_FP16)))
+    if (backend == DNN_BACKEND_INFERENCE_ENGINE)
         throw SkipTestException("");
     LayerParams lp;
     lp.name = "testPriorBox";
@@ -791,7 +790,8 @@ TEST_P(Test_Caffe_layers, PriorBox_squares)
                                        0.25, 0.0, 1.0, 1.0,
                                        0.1f, 0.1f, 0.2f, 0.2f,
                                        0.1f, 0.1f, 0.2f, 0.2f);
-    normAssert(out.reshape(1, 4), ref);
+    double l1 = (target == DNN_TARGET_OPENCL_FP16 || target == DNN_TARGET_MYRIAD) ? 2e-5 : 1e-5;
+    normAssert(out.reshape(1, 4), ref, "", l1);
 }
 
 typedef TestWithParam<tuple<int, int> > Layer_Test_DWconv_Prelu;