diff --git a/include/config.h b/include/config.h
index 4ec23b52..96086749 100644
--- a/include/config.h
+++ b/include/config.h
@@ -274,8 +274,8 @@ public:
     void setDefaultSecondaryTileset(QString tilesetName);
     void setFilePath(QString pathId, QString path);
     void setFilePath(ProjectFilePath pathId, QString path);
-    QString getFilePath(QString defaultPath, bool allowDefault = true);
-    QString getFilePath(ProjectFilePath pathId, bool allowDefault = true);
+    QString getFilePath(QString defaultPath, bool customOnly = false);
+    QString getFilePath(ProjectFilePath pathId, bool customOnly = false);
     void setPrefabFilepath(QString filepath);
     QString getPrefabFilepath();
     void setPrefabImportPrompted(bool prompted);
diff --git a/include/ui/projectsettingseditor.h b/include/ui/projectsettingseditor.h
index 5f4fcd31..83fe741e 100644
--- a/include/ui/projectsettingseditor.h
+++ b/include/ui/projectsettingseditor.h
@@ -30,6 +30,7 @@ private:
     bool hasUnsavedChanges = false;
     bool projectNeedsReload = false;
     bool refreshing = false;
+    const QString baseDir;
 
     void initUi();
     void connectSignals();
@@ -42,6 +43,7 @@ private:
     bool promptRestoreDefaults();
 
     void createProjectPathsTable();
+    QString chooseProjectFile(const QString &defaultFilepath);
 
 private slots:
     void dialogButtonClicked(QAbstractButton *button);
diff --git a/src/config.cpp b/src/config.cpp
index 9592ca63..8c51de9f 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -804,18 +804,29 @@ void ProjectConfig::setFilePath(QString defaultPath, QString newPath) {
     this->setFilePath(reverseDefaultPaths(defaultPath), newPath);
 }
 
-QString ProjectConfig::getFilePath(ProjectFilePath pathId, bool allowDefault) {
-    if (this->filePaths.contains(pathId)) {
-        return this->filePaths[pathId];
-    } else if (allowDefault && defaultPaths.contains(pathId)) {
-        return defaultPaths[pathId].second;
-    } else {
-        return QString();
+QString ProjectConfig::getFilePath(ProjectFilePath pathId, bool customOnly) {
+    const QString customPath = this->filePaths.value(pathId);
+
+    // When reading custom filepaths for the settings editor we don't care
+    // about the default path or whether the custom path exists.
+    if (customOnly)
+        return customPath;
+
+    if (!customPath.isEmpty()) {
+        // A custom filepath has been specified. If the file/folder exists, use that.
+        const QString absCustomPath = this->projectDir + QDir::separator() + customPath;
+        if (QFileInfo::exists(absCustomPath)) {
+            return customPath;
+        } else {
+            logError(QString("Custom project filepath '%1' not found. Using default.").arg(absCustomPath));
+        }
     }
+    return defaultPaths.contains(pathId) ? defaultPaths[pathId].second : QString();
+
 }
 
-QString ProjectConfig::getFilePath(QString defaultPath, bool allowDefault) {
-    return this->getFilePath(reverseDefaultPaths(defaultPath), allowDefault);
+QString ProjectConfig::getFilePath(QString defaultPath, bool customOnly) {
+    return this->getFilePath(reverseDefaultPaths(defaultPath), customOnly);
 }
 
 void ProjectConfig::setBaseGameVersion(BaseGameVersion baseGameVersion) {
diff --git a/src/ui/projectsettingseditor.cpp b/src/ui/projectsettingseditor.cpp
index 502eaca9..cfd330eb 100644
--- a/src/ui/projectsettingseditor.cpp
+++ b/src/ui/projectsettingseditor.cpp
@@ -14,7 +14,8 @@
 ProjectSettingsEditor::ProjectSettingsEditor(QWidget *parent, Project *project) :
     QMainWindow(parent),
     ui(new Ui::ProjectSettingsEditor),
-    project(project)
+    project(project),
+    baseDir(userConfig.getProjectDir() + QDir::separator())
 {
     ui->setupUi(this);
     setAttribute(Qt::WA_DeleteOnClose);
@@ -84,25 +85,54 @@ void ProjectSettingsEditor::createProjectPathsTable() {
         name->setAlignment(Qt::AlignBottom);
         name->setText(pathPair.first);
 
-        // Editable area of the path
-        auto path = new QLineEdit();
-        path->setObjectName(pathPair.first); // Used when saving the paths
-        path->setPlaceholderText(pathPair.second);
-        path->setClearButtonEnabled(true);
+        // Filepath line edit
+        auto lineEdit = new QLineEdit();
+        lineEdit->setObjectName(pathPair.first); // Used when saving the paths
+        lineEdit->setPlaceholderText(pathPair.second);
+        lineEdit->setClearButtonEnabled(true);
+
+        // "Choose file" button
         auto button = new QToolButton();
         button->setIcon(QIcon(":/icons/folder.ico"));
-        // TODO: file prompt
-        //connect(button, &QAbstractButton::clicked, this, &ProjectSettingsEditor::);
+        connect(button, &QAbstractButton::clicked, [this, lineEdit](bool) {
+            const QString path = this->chooseProjectFile(lineEdit->placeholderText());
+            if (!path.isEmpty()) {
+                lineEdit->setText(path);
+                this->markEdited();
+            }
+        });
 
         // Add to list
         auto editArea = new QWidget();
         auto layout = new QHBoxLayout(editArea);
-        layout->addWidget(path);
+        layout->addWidget(lineEdit);
         layout->addWidget(button);
         ui->layout_ProjectPaths->addRow(name, editArea);
     }
 }
 
+QString ProjectSettingsEditor::chooseProjectFile(const QString &defaultFilepath) {
+    const QString startDir = this->baseDir + defaultFilepath;
+
+    QString path;
+    if (defaultFilepath.endsWith("/")){
+        // Default filepath is a folder, choose a new folder
+        path = QFileDialog::getExistingDirectory(this, "Choose Project File Folder", startDir) + QDir::separator();
+    } else{
+        // Default filepath is not a folder, choose a new file
+        path = QFileDialog::getOpenFileName(this, "Choose Project File", startDir);
+    }
+
+    if (!path.startsWith(this->baseDir)){
+        // Most of Porymap's file-parsing code for project files will assume that filepaths
+        // are relative to the root project folder, so we enforce that here.
+        QMessageBox::warning(this, "Failed to set custom filepath",
+                           QString("Custom filepaths must be inside the root project folder '%1'").arg(this->baseDir));
+        return QString();
+    }
+    return path.remove(0, this->baseDir.length());
+}
+
 void ProjectSettingsEditor::restoreWindowState() {
     logInfo("Restoring project settings editor geometry from previous session.");
     const QMap<QString, QByteArray> geometry = porymapConfig.getProjectSettingsEditorGeometry();
@@ -149,7 +179,7 @@ void ProjectSettingsEditor::refresh() {
     ui->lineEdit_BorderMetatiles->setText(projectConfig.getNewMapBorderMetatileIdsString());
     ui->lineEdit_PrefabsPath->setText(projectConfig.getPrefabFilepath());
     for (auto lineEdit : ui->scrollAreaContents_ProjectPaths->findChildren<QLineEdit*>())
-        lineEdit->setText(projectConfig.getFilePath(lineEdit->objectName(), false));
+        lineEdit->setText(projectConfig.getFilePath(lineEdit->objectName(), true));
 
     this->refreshing = false; // Allow signals
 }
@@ -221,9 +251,8 @@ void ProjectSettingsEditor::choosePrefabsFileClicked(bool) {
     this->project->setImportExportPath(filepath);
 
     // Display relative path if this file is in the project folder
-    const QString projectDir = projectConfig.getProjectDir() + QDir::separator();
-    if (filepath.startsWith(projectDir))
-        filepath.remove(0, projectDir.length());
+    if (filepath.startsWith(this->baseDir))
+        filepath.remove(0, this->baseDir.length());
     ui->lineEdit_PrefabsPath->setText(filepath);
     this->hasUnsavedChanges = true;
 }