diff --git a/gui/manualtest/projectfiledialog.md b/gui/manualtest/projectfiledialog.md
index f11b030f246..ce7d39b1df0 100644
--- a/gui/manualtest/projectfiledialog.md
+++ b/gui/manualtest/projectfiledialog.md
@@ -4,6 +4,20 @@
 Some manual testing in the project file dialog interface
 
 
+## Test: Relative paths
+
+Ticket: #14983
+
+1. Configure files/paths in project folder:
+ * import a projectfile
+ * add include paths in project folder
+ * exclude file/folder
+
+2. Save project
+
+EXPECTED: Relative paths should be used in the XML
+
+
 ## Test: Platform file pic8.xml
 
 Ticket: #14489
diff --git a/gui/projectfile.cpp b/gui/projectfile.cpp
index 9144f5a6117..716288d9695 100644
--- a/gui/projectfile.cpp
+++ b/gui/projectfile.cpp
@@ -1193,6 +1193,15 @@ QStringList ProjectFile::getSearchPaths(const QString& projectPath, const QStrin
     return ret;
 }
 
+QString ProjectFile::getRelativePath(const QString &absolutePath) const
+{
+    const QDir dir(QFileInfo(mFilename).absolutePath());
+    const QString relativePath(dir.relativeFilePath(absolutePath));
+    if (relativePath.startsWith("../../..") || absolutePath.length() < relativePath.length())
+        return absolutePath;
+    return relativePath;
+}
+
 QStringList ProjectFile::getSearchPaths(const QString& dir) const {
     const QFileInfo inf(mFilename);
     const QString applicationFilePath = QCoreApplication::applicationFilePath();
diff --git a/gui/projectfile.h b/gui/projectfile.h
index 5a5e0ccb89b..e0b85582c99 100644
--- a/gui/projectfile.h
+++ b/gui/projectfile.h
@@ -447,6 +447,14 @@ class ProjectFile : public QObject {
 
     static QStringList getSearchPaths(const QString& projectPath, const QString& appPath, const QString& datadir, const QString& dir);
 
+    /**
+     * @brief Convert an absolute path to a path relative to this project's directory.
+     * If the relative path would need to walk up more than 2 parent folders
+     * (i.e. "../../...") the absolute path is returned unchanged instead.
+     * @param absolutePath Absolute path to convert.
+     */
+    QString getRelativePath(const QString &absolutePath) const;
+
     /** Set user includes in settings if non-empty */
     void setSettingsUserIncludes(Settings &settings) const;
 
diff --git a/gui/projectfiledialog.cpp b/gui/projectfiledialog.cpp
index 72e3d651471..abb7b343ec1 100644
--- a/gui/projectfiledialog.cpp
+++ b/gui/projectfiledialog.cpp
@@ -571,10 +571,7 @@ QString ProjectFileDialog::getExistingDirectory(const QString &caption, bool tra
 
     // Check if the path is relative to project file's path and if so
     // make it a relative path instead of absolute path.
-    const QDir dir(projectPath);
-    const QString relpath(dir.relativeFilePath(selectedDir));
-    if (!relpath.startsWith("../.."))
-        selectedDir = relpath;
+    selectedDir = mProjectFile->getRelativePath(selectedDir);
 
     // Trailing slash..
     if (trailingSlash && !selectedDir.endsWith('/'))
@@ -631,7 +628,7 @@ void ProjectFileDialog::browseImportProject()
                                                     dir.canonicalPath(),
                                                     toFilterString(filters));
     if (!fileName.isEmpty()) {
-        mUI->mEditImportProject->setText(dir.relativeFilePath(fileName));
+        mUI->mEditImportProject->setText(mProjectFile->getRelativePath(fileName));
         updatePathsAndDefines();
         setProjectConfigurations(getProjectConfigs(fileName));
         for (int row = 0; row < mUI->mListVsConfigs->count(); ++row) {
@@ -652,7 +649,7 @@ void ProjectFileDialog::browseUserInclude()
                                                     dir.canonicalPath(),
                                                     toFilterString(filters));
     if (!fileName.isEmpty()) {
-        mUI->mEditUserInclude->setText(dir.relativeFilePath(fileName));
+        mUI->mEditUserInclude->setText(mProjectFile->getRelativePath(fileName));
     }
 }
 
@@ -891,7 +888,9 @@ void ProjectFileDialog::addExcludeFile()
     QMap<QString,QString> filters;
     filters[tr("Source files")] = "*.c *.cpp";
     filters[tr("All files")] = "*.*";
-    addExcludePath(QFileDialog::getOpenFileName(this, tr("Exclude file"), dir.canonicalPath(), toFilterString(filters)));
+    QString fileName = QFileDialog::getOpenFileName(this, tr("Exclude file"), dir.canonicalPath(), toFilterString(filters));
+    if (!fileName.isEmpty())
+        addExcludePath(mProjectFile->getRelativePath(fileName));
 }
 
 void ProjectFileDialog::editExcludePath()
diff --git a/gui/test/projectfile/testprojectfile.cpp b/gui/test/projectfile/testprojectfile.cpp
index efc1dce6c4f..1a66bd8de23 100644
--- a/gui/test/projectfile/testprojectfile.cpp
+++ b/gui/test/projectfile/testprojectfile.cpp
@@ -214,5 +214,45 @@ void TestProjectFile::emptyUserInclude() const
     QCOMPARE(settings.userIncludes.size(), 0);
 }
 
+// Absolute path is made relative when it does not require walking up more than 3 parent folders
+void TestProjectFile::getRelativePathRelative() const
+{
+    ProjectFile projectFile;
+    projectFile.setFilename("/some/path/sub/123.cppcheck");
+    QCOMPARE(projectFile.getRelativePath("/some/path/externals/foo.cpp"), QString("../externals/foo.cpp"));
+}
+
+// Absolute path is made relative even when it requires walking up 2 parent folders
+void TestProjectFile::getRelativePathTwoUp() const
+{
+    ProjectFile projectFile;
+    projectFile.setFilename("/some/path/sub/123.cppcheck");
+    QCOMPARE(projectFile.getRelativePath("/some/externals/foo.cpp"), QString("../../externals/foo.cpp"));
+}
+
+// Absolute path is kept as-is when making it relative would require walking up more than 3 parent folders
+void TestProjectFile::getRelativePathTooFarUp() const
+{
+    ProjectFile projectFile;
+    projectFile.setFilename("/some/path/sub/123.cppcheck");
+    QCOMPARE(projectFile.getRelativePath("/other/deep/foo.cpp"), QString("/other/deep/foo.cpp"));
+}
+
+// Absolute path in a subfolder of the project path is made relative without walking up at all
+void TestProjectFile::getRelativePathSubfolder() const
+{
+    ProjectFile projectFile;
+    projectFile.setFilename("/some/path/sub/123.cppcheck");
+    QCOMPARE(projectFile.getRelativePath("/some/path/sub/src/file1.c"), QString("src/file1.c"));
+}
+
+// Absolute path is kept as-is when it is shorter than the relative path, even if it does not require walking up 3 or more parent folders
+void TestProjectFile::getRelativePathAbsoluteShorter() const
+{
+    ProjectFile projectFile;
+    projectFile.setFilename("/ab/path/sub/123.cppcheck");
+    QCOMPARE(projectFile.getRelativePath("/ab/foo.cpp"), QString("/ab/foo.cpp"));
+}
+
 QTEST_MAIN(TestProjectFile)
 
diff --git a/gui/test/projectfile/testprojectfile.h b/gui/test/projectfile/testprojectfile.h
index ceda2ff6b96..7203980eb7c 100644
--- a/gui/test/projectfile/testprojectfile.h
+++ b/gui/test/projectfile/testprojectfile.h
@@ -38,4 +38,10 @@ private slots:
     void getCheckingSuppressionsStar() const;
 
     void emptyUserInclude() const;
+
+    void getRelativePathRelative() const;
+    void getRelativePathTwoUp() const;
+    void getRelativePathTooFarUp() const;
+    void getRelativePathSubfolder() const;
+    void getRelativePathAbsoluteShorter() const;
 };