diff --git a/pyani/scripts/parsers/plot_parser.py b/pyani/scripts/parsers/plot_parser.py
index 1de228e3..c5a4da6c 100644
--- a/pyani/scripts/parsers/plot_parser.py
+++ b/pyani/scripts/parsers/plot_parser.py
@@ -104,4 +104,13 @@ def build(
         help="graphics method to use for plotting",
         choices=["seaborn", "mpl", "plotly"],
     )
+    parser.add_argument(
+        "--workers",
+        dest="workers",
+        action="store",
+        default=None,
+        type=int,
+        help="Number of worker processes for multiprocessing "
+        "(default zero, meaning use all available cores)",
+    )
     parser.set_defaults(func=subcommands.subcmd_plot)
diff --git a/pyani/scripts/subcommands/subcmd_plot.py b/pyani/scripts/subcommands/subcmd_plot.py
index 8c3d9887..dbd156cd 100644
--- a/pyani/scripts/subcommands/subcmd_plot.py
+++ b/pyani/scripts/subcommands/subcmd_plot.py
@@ -41,6 +41,7 @@
 
 import logging
 import os
+import multiprocessing
 
 from argparse import Namespace
 from pathlib import Path
@@ -90,14 +91,12 @@ def subcmd_plot(args: Namespace) -> int:
     run_ids = [int(run) for run in args.run_id.split(",")]
     logger.debug("Generating graphics for runs: %s", run_ids)
     for run_id in run_ids:
-        write_run_heatmaps(run_id, session, outfmts, args)
+        write_run_plots(run_id, session, outfmts, args)
 
     return 0
 
 
-def write_run_heatmaps(
-    run_id: int, session, outfmts: List[str], args: Namespace
-) -> None:
+def write_run_plots(run_id: int, session, outfmts: List[str], args: Namespace) -> None:
     """Write all heatmaps for a specified run to file.
 
     :param run_id:  int, run identifier in database session
@@ -118,7 +117,13 @@ def write_run_heatmaps(
         f"Have {len(result_label_dict)} labels and {len(result_class_dict)} classes"
     )
 
-    # Write heatmap for each results matrix
+    # Write heatmap and distribution plot for each results matrix
+
+    # Create worker pool and empty command list
+    pool = multiprocessing.Pool(processes=args.workers)
+    plotting_commands = []
+
+    # Build and collect the plotting commands
     for matdata in [
         MatrixData(*_)
         for _ in [
@@ -129,20 +134,39 @@ def write_run_heatmaps(
             ("hadamard", pd.read_json(results.df_hadamard), {}),
         ]
     ]:
-        write_heatmap(
-            run_id, matdata, result_label_dict, result_class_dict, outfmts, args
+        plotting_commands.append(
+            (
+                write_heatmap,
+                [run_id, matdata, result_label_dict, result_class_dict, outfmts, args],
+            )
+        )
+        plotting_commands.append((write_distribution, [run_id, matdata, outfmts, args]))
+
+    id_matrix = MatrixData("identity", pd.read_json(results.df_identity), {})
+    cov_matrix = MatrixData("coverage", pd.read_json(results.df_coverage), {})
+    plotting_commands.append(
+        (
+            write_scatter,
+            [
+                run_id,
+                id_matrix,
+                cov_matrix,
+                result_label_dict,
+                result_class_dict,
+                outfmts,
+                args,
+            ],
         )
-        write_distribution(run_id, matdata, outfmts, args)
-    write_scatter(
-        run_id,
-        MatrixData("identity", pd.read_json(results.df_identity), {}),
-        MatrixData("coverage", pd.read_json(results.df_coverage), {}),
-        result_label_dict,
-        result_class_dict,
-        outfmts,
-        args,
     )
 
+    # Run the plotting commands
+    for func, options in plotting_commands:
+        pool.apply_async(func, options, {})
+
+    # Close worker pool
+    pool.close()
+    pool.join()
+
 
 def write_distribution(
     run_id: int,
diff --git a/requirements.txt b/requirements.txt
index 79f24435..15d97e59 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 biopython
+ete3
 matplotlib
 namedlist
 networkx
@@ -6,6 +7,7 @@ numpy
 openpyxl
 pandas
 Pillow
+PyQt5
 scipy
 seaborn
 sqlalchemy==1.3.10
diff --git a/tests/test_subcmd_06_plot.py b/tests/test_subcmd_06_plot.py
index 16b96bbe..989a1e7f 100644
--- a/tests/test_subcmd_06_plot.py
+++ b/tests/test_subcmd_06_plot.py
@@ -80,6 +80,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="pdf",
                 method="mpl",
+                workers=None,
             ),
             "mpl_png": Namespace(
                 outdir=self.outdir / "mpl",
@@ -87,6 +88,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="png",
                 method="mpl",
+                workers=None,
             ),
             "mpl_svg": Namespace(
                 outdir=self.outdir / "mpl",
@@ -94,6 +96,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="svg",
                 method="mpl",
+                workers=None,
             ),
             "mpl_jpg": Namespace(
                 outdir=self.outdir / "mpl",
@@ -101,6 +104,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="jpg",
                 method="mpl",
+                workers=None,
             ),
             "seaborn_pdf": Namespace(
                 outdir=self.outdir / "seaborn",
@@ -108,6 +112,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="pdf",
                 method="seaborn",
+                workers=None,
             ),
             "seaborn_png": Namespace(
                 outdir=self.outdir / "seaborn",
@@ -115,6 +120,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="png",
                 method="seaborn",
+                workers=None,
             ),
             "seaborn_svg": Namespace(
                 outdir=self.outdir / "seaborn",
@@ -122,6 +128,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="svg",
                 method="seaborn",
+                workers=None,
             ),
             "seaborn_jpg": Namespace(
                 outdir=self.outdir / "seaborn",
@@ -129,6 +136,7 @@ def setUp(self):
                 dbpath=self.dbpath,
                 formats="jpg",
                 method="seaborn",
+                workers=None,
             ),
         }