diff --git a/.github/workflows/unittest.yml b/.github/workflows/unittest.yml
index 46a16e8cf..fdc0e9666 100644
--- a/.github/workflows/unittest.yml
+++ b/.github/workflows/unittest.yml
@@ -14,7 +14,6 @@ on:
       - "Makefile"
       - "MANIFEST.in"
       - "pyproject.toml"
-      - "tox.ini"
   pull_request:
     branches:
       - dev
@@ -27,7 +26,6 @@ on:
       - "Makefile"
       - "MANIFEST.in"
       - "pyproject.toml"
-      - "tox.ini"
 
 jobs:
   unittest:
diff --git a/pyproject.toml b/pyproject.toml
index cfe4554e4..4c554beec 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -318,3 +318,18 @@ select = [
 # Some rules are ignored for now; we can consider enabling them in the future.
 # S101 is use of assert statement, should be an easy fix.
 extend-ignore = ["E402", "E501", "E722", "S101", "S202", "S301", "S310"]
+
+[tool.tox]
+envlist = ["py39", "py310", "py311", "py312", "py313", "py3", "flake8"]
+skip_missing_interpreters = true
+
+[tool.tox.testenv]
+setenv = { PYTHONPATH = "{toxinidir}:{toxinidir}/pythainlp" }
+changedir = "tests"
+commands = ["discover"]
+deps = ["discover"]
+
+[tool.tox.envs.flake8]
+basepython = "python"
+deps = ["flake8"]
+commands = ["flake8 pythainlp"]
diff --git a/tox.ini b/tox.ini
deleted file mode 100644
index 59ee3c9dd..000000000
--- a/tox.ini
+++ /dev/null
@@ -1,19 +0,0 @@
-[tox]
-envlist=py{39,310,311,312,313,py3},flake8
-skip_missing_interpreters = true
-
-[testenv]
-setenv = PYTHONPATH = {toxinidir}:{toxinidir}/pythainlp
-#commands = python3 -m unittest discover
-changedir = tests
-commands = discover
-deps = discover
-;  If you want to install the package with dependencies for testing:
-; deps =
-;     .[compact]
-;     discover
-
-[testenv:flake8]
-basepython = python
-deps = flake8
-commands = flake8 pythainlp