diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 00000000..8bd1689c
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,3 @@
+[build-system]
+requires = ['setuptools>=61.0']
+build-backend   = 'setuptools.build_meta'
\ No newline at end of file
diff --git a/run_tests.py b/run_tests.py
index c2bafe00..bf5d7c4e 100644
--- a/run_tests.py
+++ b/run_tests.py
@@ -1,4 +1,4 @@
 import unittest
 
 if __name__ == '__main__':
-    unittest.main('flowkit.tests')
+    unittest.main('tests')
diff --git a/setup.py b/setup.py
index 61ce1080..3a13cf2d 100644
--- a/setup.py
+++ b/setup.py
@@ -4,7 +4,7 @@
 from setuptools import setup, find_packages
 
 # read in version string
-VERSION_FILE = 'flowkit/_version.py'
+VERSION_FILE = 'src/flowkit/_version.py'
 __version__ = None  # to avoid inspection warning and check if __version__ was loaded
 exec(open(VERSION_FILE).read())
 
@@ -31,7 +31,8 @@
 setup(
     name='FlowKit',
     version=__version__,  # noqa PyTypeChecker
-    packages=find_packages(exclude=["flowkit/tests/"]),
+    packages=['flowkit'],
+    package_dir={'': 'src'},
     package_data={'': ['_resources/*.xsd']},
     include_package_data=True,
     description='Flow Cytometry Toolkit',
diff --git a/flowkit/__init__.py b/src/flowkit/__init__.py
similarity index 100%
rename from flowkit/__init__.py
rename to src/flowkit/__init__.py
diff --git a/flowkit/_conf.py b/src/flowkit/_conf.py
similarity index 100%
rename from flowkit/_conf.py
rename to src/flowkit/_conf.py
diff --git a/flowkit/_models/__init__.py b/src/flowkit/_models/__init__.py
similarity index 100%
rename from flowkit/_models/__init__.py
rename to src/flowkit/_models/__init__.py
diff --git a/flowkit/_models/dimension.py b/src/flowkit/_models/dimension.py
similarity index 100%
rename from flowkit/_models/dimension.py
rename to src/flowkit/_models/dimension.py
diff --git a/flowkit/_models/gate_node.py b/src/flowkit/_models/gate_node.py
similarity index 100%
rename from flowkit/_models/gate_node.py
rename to src/flowkit/_models/gate_node.py
diff --git a/flowkit/_models/gates/__init__.py b/src/flowkit/_models/gates/__init__.py
similarity index 100%
rename from flowkit/_models/gates/__init__.py
rename to src/flowkit/_models/gates/__init__.py
diff --git a/flowkit/_models/gates/_base_gate.py b/src/flowkit/_models/gates/_base_gate.py
similarity index 100%
rename from flowkit/_models/gates/_base_gate.py
rename to src/flowkit/_models/gates/_base_gate.py
diff --git a/flowkit/_models/gates/_gates.py b/src/flowkit/_models/gates/_gates.py
similarity index 100%
rename from flowkit/_models/gates/_gates.py
rename to src/flowkit/_models/gates/_gates.py
diff --git a/flowkit/_models/gates/_gml_gates.py b/src/flowkit/_models/gates/_gml_gates.py
similarity index 100%
rename from flowkit/_models/gates/_gml_gates.py
rename to src/flowkit/_models/gates/_gml_gates.py
diff --git a/flowkit/_models/gates/_wsp_gates.py b/src/flowkit/_models/gates/_wsp_gates.py
similarity index 100%
rename from flowkit/_models/gates/_wsp_gates.py
rename to src/flowkit/_models/gates/_wsp_gates.py
diff --git a/flowkit/_models/gating_results.py b/src/flowkit/_models/gating_results.py
similarity index 100%
rename from flowkit/_models/gating_results.py
rename to src/flowkit/_models/gating_results.py
diff --git a/flowkit/_models/gating_strategy.py b/src/flowkit/_models/gating_strategy.py
similarity index 100%
rename from flowkit/_models/gating_strategy.py
rename to src/flowkit/_models/gating_strategy.py
diff --git a/flowkit/_models/sample.py b/src/flowkit/_models/sample.py
similarity index 100%
rename from flowkit/_models/sample.py
rename to src/flowkit/_models/sample.py
diff --git a/flowkit/_models/session.py b/src/flowkit/_models/session.py
similarity index 100%
rename from flowkit/_models/session.py
rename to src/flowkit/_models/session.py
diff --git a/flowkit/_models/transforms/__init__.py b/src/flowkit/_models/transforms/__init__.py
similarity index 100%
rename from flowkit/_models/transforms/__init__.py
rename to src/flowkit/_models/transforms/__init__.py
diff --git a/flowkit/_models/transforms/_base_transform.py b/src/flowkit/_models/transforms/_base_transform.py
similarity index 100%
rename from flowkit/_models/transforms/_base_transform.py
rename to src/flowkit/_models/transforms/_base_transform.py
diff --git a/flowkit/_models/transforms/_matrix.py b/src/flowkit/_models/transforms/_matrix.py
similarity index 100%
rename from flowkit/_models/transforms/_matrix.py
rename to src/flowkit/_models/transforms/_matrix.py
diff --git a/flowkit/_models/transforms/_transforms.py b/src/flowkit/_models/transforms/_transforms.py
similarity index 100%
rename from flowkit/_models/transforms/_transforms.py
rename to src/flowkit/_models/transforms/_transforms.py
diff --git a/flowkit/_models/transforms/_wsp_transforms.py b/src/flowkit/_models/transforms/_wsp_transforms.py
similarity index 100%
rename from flowkit/_models/transforms/_wsp_transforms.py
rename to src/flowkit/_models/transforms/_wsp_transforms.py
diff --git a/flowkit/_models/workspace.py b/src/flowkit/_models/workspace.py
similarity index 100%
rename from flowkit/_models/workspace.py
rename to src/flowkit/_models/workspace.py
diff --git a/flowkit/_resources/DataTypes.v2.0.xsd b/src/flowkit/_resources/DataTypes.v2.0.xsd
similarity index 100%
rename from flowkit/_resources/DataTypes.v2.0.xsd
rename to src/flowkit/_resources/DataTypes.v2.0.xsd
diff --git a/flowkit/_resources/Gating-ML.v2.0.xsd b/src/flowkit/_resources/Gating-ML.v2.0.xsd
similarity index 100%
rename from flowkit/_resources/Gating-ML.v2.0.xsd
rename to src/flowkit/_resources/Gating-ML.v2.0.xsd
diff --git a/flowkit/_resources/Transformations.v2.0.xsd b/src/flowkit/_resources/Transformations.v2.0.xsd
similarity index 100%
rename from flowkit/_resources/Transformations.v2.0.xsd
rename to src/flowkit/_resources/Transformations.v2.0.xsd
diff --git a/flowkit/_resources/__init__.py b/src/flowkit/_resources/__init__.py
similarity index 100%
rename from flowkit/_resources/__init__.py
rename to src/flowkit/_resources/__init__.py
diff --git a/flowkit/_utils/__init__.py b/src/flowkit/_utils/__init__.py
similarity index 100%
rename from flowkit/_utils/__init__.py
rename to src/flowkit/_utils/__init__.py
diff --git a/flowkit/_utils/gating_utils.py b/src/flowkit/_utils/gating_utils.py
similarity index 100%
rename from flowkit/_utils/gating_utils.py
rename to src/flowkit/_utils/gating_utils.py
diff --git a/flowkit/_utils/gml_write.py b/src/flowkit/_utils/gml_write.py
similarity index 100%
rename from flowkit/_utils/gml_write.py
rename to src/flowkit/_utils/gml_write.py
diff --git a/flowkit/_utils/plot_utils.py b/src/flowkit/_utils/plot_utils.py
similarity index 100%
rename from flowkit/_utils/plot_utils.py
rename to src/flowkit/_utils/plot_utils.py
diff --git a/flowkit/_utils/sample_utils.py b/src/flowkit/_utils/sample_utils.py
similarity index 100%
rename from flowkit/_utils/sample_utils.py
rename to src/flowkit/_utils/sample_utils.py
diff --git a/flowkit/_utils/wsp_utils.py b/src/flowkit/_utils/wsp_utils.py
similarity index 100%
rename from flowkit/_utils/wsp_utils.py
rename to src/flowkit/_utils/wsp_utils.py
diff --git a/flowkit/_utils/xml_common.py b/src/flowkit/_utils/xml_common.py
similarity index 100%
rename from flowkit/_utils/xml_common.py
rename to src/flowkit/_utils/xml_common.py
diff --git a/flowkit/_utils/xml_utils.py b/src/flowkit/_utils/xml_utils.py
similarity index 100%
rename from flowkit/_utils/xml_utils.py
rename to src/flowkit/_utils/xml_utils.py
diff --git a/flowkit/_version.py b/src/flowkit/_version.py
similarity index 100%
rename from flowkit/_version.py
rename to src/flowkit/_version.py
diff --git a/flowkit/exceptions.py b/src/flowkit/exceptions.py
similarity index 100%
rename from flowkit/exceptions.py
rename to src/flowkit/exceptions.py
diff --git a/flowkit/tests/__init__.py b/tests/__init__.py
similarity index 100%
rename from flowkit/tests/__init__.py
rename to tests/__init__.py
diff --git a/flowkit/tests/export_gml_tests.py b/tests/export_gml_tests.py
similarity index 99%
rename from flowkit/tests/export_gml_tests.py
rename to tests/export_gml_tests.py
index cce51379..135032c3 100644
--- a/flowkit/tests/export_gml_tests.py
+++ b/tests/export_gml_tests.py
@@ -2,16 +2,12 @@
 Tests for exporting to GatingML
 """
 import unittest
-import sys
-import os
 import glob
 import re
 from io import BytesIO
 import numpy as np
 import pandas as pd
 
-sys.path.append(os.path.abspath('../..'))
-
 from flowkit import Sample, Session
 
 data1_fcs_path = 'data/gate_ref/data1.fcs'
diff --git a/flowkit/tests/gate_tests.py b/tests/gate_tests.py
similarity index 100%
rename from flowkit/tests/gate_tests.py
rename to tests/gate_tests.py
diff --git a/flowkit/tests/gating_results_tests.py b/tests/gating_results_tests.py
similarity index 100%
rename from flowkit/tests/gating_results_tests.py
rename to tests/gating_results_tests.py
diff --git a/flowkit/tests/gating_strategy_custom_gates_tests.py b/tests/gating_strategy_custom_gates_tests.py
similarity index 97%
rename from flowkit/tests/gating_strategy_custom_gates_tests.py
rename to tests/gating_strategy_custom_gates_tests.py
index 1a2aaae6..530afd8c 100644
--- a/flowkit/tests/gating_strategy_custom_gates_tests.py
+++ b/tests/gating_strategy_custom_gates_tests.py
@@ -2,13 +2,9 @@
 Tests for custom gates in the GatingStrategy Class
 """
 import copy
-import os
-import sys
 import unittest
 import flowkit as fk
 
-sys.path.append(os.path.abspath('../..'))
-
 
 class GatingStrategyCustomGatesTestCase(unittest.TestCase):
     def setUp(self):
diff --git a/flowkit/tests/gating_strategy_prog_gate_tests.py b/tests/gating_strategy_prog_gate_tests.py
similarity index 99%
rename from flowkit/tests/gating_strategy_prog_gate_tests.py
rename to tests/gating_strategy_prog_gate_tests.py
index 3c59ceb5..10d230a9 100644
--- a/flowkit/tests/gating_strategy_prog_gate_tests.py
+++ b/tests/gating_strategy_prog_gate_tests.py
@@ -3,13 +3,9 @@
 """
 import copy
 import unittest
-import sys
-import os
 import numpy as np
 import pandas as pd
 
-sys.path.append(os.path.abspath('../..'))
-
 import flowkit as fk
 
 data1_fcs_path = 'data/gate_ref/data1.fcs'
diff --git a/flowkit/tests/gating_strategy_remove_gates_tests.py b/tests/gating_strategy_remove_gates_tests.py
similarity index 100%
rename from flowkit/tests/gating_strategy_remove_gates_tests.py
rename to tests/gating_strategy_remove_gates_tests.py
diff --git a/flowkit/tests/gating_strategy_reused_gates_tests.py b/tests/gating_strategy_reused_gates_tests.py
similarity index 100%
rename from flowkit/tests/gating_strategy_reused_gates_tests.py
rename to tests/gating_strategy_reused_gates_tests.py
diff --git a/flowkit/tests/gating_strategy_tests.py b/tests/gating_strategy_tests.py
similarity index 100%
rename from flowkit/tests/gating_strategy_tests.py
rename to tests/gating_strategy_tests.py
diff --git a/flowkit/tests/gatingml_tests.py b/tests/gatingml_tests.py
similarity index 99%
rename from flowkit/tests/gatingml_tests.py
rename to tests/gatingml_tests.py
index c7204e77..c8d3a257 100644
--- a/flowkit/tests/gatingml_tests.py
+++ b/tests/gatingml_tests.py
@@ -1,14 +1,10 @@
 import unittest
-import sys
-import os
 import glob
 import re
 import numpy as np
 import pandas as pd
 
-sys.path.append(os.path.abspath('../..'))
-
-from flowkit import Sample, GatingStrategy, Session, gates, parse_gating_xml
+from flowkit import Sample, GatingStrategy, Session, parse_gating_xml
 
 data1_fcs_path = 'data/gate_ref/data1.fcs'
 data1_sample = Sample(data1_fcs_path)
diff --git a/flowkit/tests/matrix_tests.py b/tests/matrix_tests.py
similarity index 100%
rename from flowkit/tests/matrix_tests.py
rename to tests/matrix_tests.py
diff --git a/flowkit/tests/plot_tests.py b/tests/plot_tests.py
similarity index 100%
rename from flowkit/tests/plot_tests.py
rename to tests/plot_tests.py
diff --git a/flowkit/tests/sample_export_tests.py b/tests/sample_export_tests.py
similarity index 100%
rename from flowkit/tests/sample_export_tests.py
rename to tests/sample_export_tests.py
diff --git a/flowkit/tests/sample_tests.py b/tests/sample_tests.py
similarity index 99%
rename from flowkit/tests/sample_tests.py
rename to tests/sample_tests.py
index 35e6e56d..d8e0d880 100644
--- a/flowkit/tests/sample_tests.py
+++ b/tests/sample_tests.py
@@ -3,16 +3,12 @@
 """
 import copy
 import unittest
-import sys
-import os
 from pathlib import Path
 import numpy as np
 import pandas as pd
 import flowio
 import warnings
 
-sys.path.append(os.path.abspath('../..'))
-
 from flowkit import Sample, transforms, read_multi_dataset_fcs
 from flowkit.exceptions import DataOffsetDiscrepancyError
 
diff --git a/flowkit/tests/session_export_tests.py b/tests/session_export_tests.py
similarity index 100%
rename from flowkit/tests/session_export_tests.py
rename to tests/session_export_tests.py
diff --git a/flowkit/tests/session_tests.py b/tests/session_tests.py
similarity index 98%
rename from flowkit/tests/session_tests.py
rename to tests/session_tests.py
index 6d8299b9..cd20f4f7 100644
--- a/flowkit/tests/session_tests.py
+++ b/tests/session_tests.py
@@ -3,13 +3,9 @@
 """
 import copy
 import unittest
-import sys
-import os
 import numpy as np
 import pandas as pd
 
-sys.path.append(os.path.abspath('../..'))
-
 from flowkit import Session, Sample, Matrix, Dimension, gates, transforms, load_samples
 from .gating_strategy_prog_gate_tests import data1_sample, poly1_gate, poly1_vertices, comp_matrix_01, asinh_xform1
 
diff --git a/flowkit/tests/string_repr_tests.py b/tests/string_repr_tests.py
similarity index 100%
rename from flowkit/tests/string_repr_tests.py
rename to tests/string_repr_tests.py
diff --git a/flowkit/tests/transform_tests.py b/tests/transform_tests.py
similarity index 100%
rename from flowkit/tests/transform_tests.py
rename to tests/transform_tests.py
diff --git a/flowkit/tests/workspace_tests.py b/tests/workspace_tests.py
similarity index 100%
rename from flowkit/tests/workspace_tests.py
rename to tests/workspace_tests.py