diff --git a/src/sage/combinat/posets/posets.py b/src/sage/combinat/posets/posets.py
index 9315781555e..06bac0c4be5 100644
--- a/src/sage/combinat/posets/posets.py
+++ b/src/sage/combinat/posets/posets.py
@@ -1675,7 +1675,7 @@ def plot(self, label_elements=True, element_labels=None,
           * ``element_color`` - a color for elements not set in
             ``element_colors``
           * ``element_shape`` - the shape of elements, like ``'s'`` for
-            square; see http://matplotlib.org/api/markers_api.html for the list
+            square; see https://matplotlib.org/api/markers_api.html for the list
           * ``element_size`` (default: 200) - the size of elements
           * ``label_elements`` (default: ``True``) - whether to display
             element labels
diff --git a/src/sage/graphs/generic_graph.py b/src/sage/graphs/generic_graph.py
index 18ca000c49c..fb37c744161 100644
--- a/src/sage/graphs/generic_graph.py
+++ b/src/sage/graphs/generic_graph.py
@@ -19446,7 +19446,7 @@ def plot(self, **options):
 
         - ``vertex_shape`` - the shape to draw the vertices, for
           example ``"o"`` for circle or ``"s"`` for square. Whole list
-          is available at http://matplotlib.org/api/markers_api.html.
+          is available at https://matplotlib.org/api/markers_api.html.
           (Not available for multiedge digraphs.)
 
         - ``graph_border`` - whether to include a box around the graph
diff --git a/src/sage/plot/graphics.py b/src/sage/plot/graphics.py
index 3e3c53b31e4..ce6c5024589 100644
--- a/src/sage/plot/graphics.py
+++ b/src/sage/plot/graphics.py
@@ -1549,7 +1549,7 @@ def show(self, **kwds):
 
           - ``"default"`` -- Uses matplotlib's internal text rendering
             engine called Mathtext ( see
-            http://matplotlib.org/users/mathtext.html ). If you have
+            https://matplotlib.org/users/mathtext.html ). If you have
             modified the default matplotlib settings, for instance via
             a matplotlibrc file, then this option will not change any of
             those settings.
@@ -3159,7 +3159,7 @@ def save(self, filename, **kwds):
                 if latex_implementations[0] == "pdflatex":
                     # use pdflatex and set font encoding as per
                     # matplotlib documentation:
-                    # http://matplotlib.org/users/pgf.html#pgf-tutorial
+                    # https://matplotlib.org/users/pgf.html#pgf-tutorial
                     pgf_options= {"pgf.texsystem": "pdflatex",
                                   "pgf.preamble": [
                                       r"\usepackage[utf8x]{inputenc}",
diff --git a/src/sage/plot/matrix_plot.py b/src/sage/plot/matrix_plot.py
index 925f3e76eff..ba6c99945a1 100644
--- a/src/sage/plot/matrix_plot.py
+++ b/src/sage/plot/matrix_plot.py
@@ -271,7 +271,7 @@ def matrix_plot(mat, **options):
 
       The list of predefined color maps can be visualized in `matplotlib's
       documentation
-      <http://matplotlib.org/examples/color/colormaps_reference.html>`__. You
+      <https://matplotlib.org/examples/color/colormaps_reference.html>`__. You
       can also type ``import matplotlib.cm; matplotlib.cm.datad.keys()`` to list
       their names.
 
diff --git a/src/sage/repl/ipython_kernel/kernel.py b/src/sage/repl/ipython_kernel/kernel.py
index d2e11b9a1da..425c8d7e11f 100644
--- a/src/sage/repl/ipython_kernel/kernel.py
+++ b/src/sage/repl/ipython_kernel/kernel.py
@@ -157,7 +157,7 @@ def help_links(self):
             },
             {
                 'text': "Matplotlib",
-                'url': "http://matplotlib.org/contents.html",
+                'url': "https://matplotlib.org/contents.html",
             },
             {
                 'text': "Markdown",