diff --git a/README.rst b/README.rst
index 45f4f67..0660497 100644
--- a/README.rst
+++ b/README.rst
@@ -32,7 +32,6 @@ Requirements
 ------------
 
 * `numpy <https://numpy.org/>`_
-* nptyping
 * typing_extensions
 
 v1.0+ requires Python 3.7 or above. If you have an older Python version, please install a v0.x release instead.
diff --git a/docs/requirements.txt b/docs/requirements.txt
index 7c1e8d2..9655cde 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,6 +1,5 @@
 sphinx==5.1.1
 sphinx-rtd-theme==1.0.0
-numpy>=1.11.1
+numpy>=1.21
 numpydoc==1.4.0
-nptyping
-typing_extensions
\ No newline at end of file
+typing_extensions
diff --git a/docs/source/index.rst b/docs/source/index.rst
index 99c0370..e6c0b69 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -27,7 +27,6 @@ Requirements
 ------------
 
 * `numpy <https://numpy.org/>`_
-* nptyping
 * typing_extensions
 
 v1.0+ requires Python 3.7 or above. If you have an older Python version, please install a v0.x release instead.
@@ -108,4 +107,4 @@ Contents
     Issue tracker <https://github.com/mhe/pynrrd/issues>
     Releases <https://github.com/mhe/pynrrd/releases>
     PyPi <https://pypi.org/project/pynrrd/>
-    License <https://github.com/mhe/pynrrd/blob/master/LICENSE>
\ No newline at end of file
+    License <https://github.com/mhe/pynrrd/blob/master/LICENSE>
diff --git a/pyproject.toml b/pyproject.toml
index 318f3eb..97688c3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,7 +22,7 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
 ]
 
-dependencies = ["numpy >=1.11.1", "nptyping", "typing_extensions"]
+dependencies = ["numpy >= 1.21", "typing_extensions"]
 
 [project.optional-dependencies]
 dev = ["build", "pre-commit", "pytest"]
diff --git a/requirements.txt b/requirements.txt
index 6aa66a5..8f20eaa 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,2 @@
-numpy>=1.11.1
-nptyping
+numpy>=1.21
 typing_extensions