diff --git a/sklearn/cluster/hierarchical.py b/sklearn/cluster/hierarchical.py
index 2195fe8ee3d85..08fd9a5a58d21 100644
--- a/sklearn/cluster/hierarchical.py
+++ b/sklearn/cluster/hierarchical.py
@@ -289,7 +289,7 @@ def ward_tree(X, connectivity=None, n_clusters=None, return_distance=False):
 
 
 # average and complete linkage
-def linkage_tree(X, connectivity=None, n_components=None,
+def linkage_tree(X, connectivity=None, n_components='deprecated',
                  n_clusters=None, linkage='complete', affinity="euclidean",
                  return_distance=False):
     """Linkage agglomerative clustering based on a Feature matrix.
@@ -365,6 +365,10 @@ def linkage_tree(X, connectivity=None, n_components=None,
     --------
     ward_tree : hierarchical clustering with ward linkage
     """
+    if n_components != 'deprecated':
+        warnings.warn("n_components was deprecated in 0.18"
+                      "will be removed in 0.21", DeprecationWarning)
+
     X = np.asarray(X)
     if X.ndim == 1:
         X = np.reshape(X, (-1, 1))
diff --git a/sklearn/cluster/tests/test_hierarchical.py b/sklearn/cluster/tests/test_hierarchical.py
index 986b92e0ce9f4..b9ca301971715 100644
--- a/sklearn/cluster/tests/test_hierarchical.py
+++ b/sklearn/cluster/tests/test_hierarchical.py
@@ -36,6 +36,20 @@
 from sklearn.utils.testing import assert_warns
 
 
+def test_deprecation_of_n_components_in_linkage_tree():
+    rng = np.random.RandomState(0)
+    X = rng.randn(50, 100)
+    # Test for warning of deprecation of n_components in linkage_tree
+    children, n_nodes, n_leaves, parent = assert_warns(DeprecationWarning,
+                                                       linkage_tree,
+                                                       X.T,
+                                                       n_components=10)
+    children_t, n_nodes_t, n_leaves_t, parent_t = linkage_tree(X.T)
+    assert_array_equal(children, children_t)
+    assert_equal(n_nodes, n_nodes_t)
+    assert_equal(n_leaves, n_leaves_t)
+    assert_equal(parent, parent_t)
+
 def test_linkage_misc():
     # Misc tests on linkage
     rng = np.random.RandomState(42)