| Accessory | Allows applet plugins to add themselves to the Q menu | 
| AlarmServer | Allows alarms to be scheduled and unscheduled | 
| AppLnk | Represents an application available on the system | 
| AppLnkSet | Set of AppLnk objects | 
| Calendar | Programmers with an easy to calculate and get information about dates, months and years | 
| Categories | Database that groups categories and maps ids to names | 
| CategoryGroup | Group of categories | 
| CategoryMenu | Aids in filtering records or files by Category | 
| CategorySelect | Allows users to select Categories with a combobox interface | 
| Config | For saving application configuration state | 
| DateBookDB | Used to access event information in the Qtopia database | 
| DeviceButton | Represents a physical user mappable button on a Qtopia device | 
| DeviceButtonManager | Manages device button mappings | 
| DocLnk | Represents loaded document references | 
| DocLnkSet | Set of DocLnk objects | 
| DocPropertiesDialog | Allows the user to examine attributes associated with a AppLnk object | 
| DocPropertiesWidget | Controls for modifying an AppLnks properties | 
| FileManager | Assists with AppLnk input/output | 
| FileSelector | Allows the user to select DocLnk objects | 
| FileSystem | Describes a single mount point | 
| FontDatabase | Information about available fonts | 
| Global | Application-wide global functions | 
| Ir | Implements basic support for sending objects over an infrared communication link | 
| LocationCombo | Displays a list of available storage locations | 
| MediaPlayerDecoder | Abstract base class for Qtopia MediaPlayer decoder plugins | 
| MediaPlayerDecoder_1_6 | Extension to the MediaPlayerDecoder class for Qtopia MediaPlayer decoder plugins | 
| MediaRecorderEncoder | Abstract base class for Qtopia MediaRecorder encoder plugins | 
| MenuButton | Pushbutton with a menu | 
| MimeType | MIME type information | 
| Node | Single element in an XML structure defined by XmlHandler | 
| PluginLoader | Simplifies plugin loading and allows plugins to be enabled/disabled | 
| QCopEnvelope | Encapsulates and sends QCop messages over QCopChannels | 
| QEucJpCodec | Conversion to and from EUC-JP character sets | 
| QJisCodec | Conversion to and from JIS character sets | 
| QJpUnicodeConv | Implementation support for QJisCodec, QSjisCodec, and QEucJpCodec | 
| QLibrary | Wrapper for handling shared libraries | 
| QPEApplication | Implements various system services that are available to all Qtopia applications | 
| QPEDateEdit | Compact widget for selecting a date | 
| QPEDatePicker | Allows a date to be selected from a calendar view | 
| QPEDateTimeEdit | Compact widget for selecting a date and time | 
| QPEMessageBox | A message box that provides yes, no and cancel options | 
| QPEStyle | Implements the default Qtopia widget style | 
| QPETimeEdit | Compact widget for selecting a time | 
| QProcess | Used to start external programs and to communicate with them | 
| QSjisCodec | Conversion to and from Shift-JIS | 
| QUuid | Defines a Universally Unique Identifier (UUID) | 
| Resource | Access to named resources | 
| Service | Allows applications to provide services for other applications to use | 
| ServiceRequest | Allows applications to request services from other applications | 
| Sound | Plays WAVE sound files and can invoke the audible alarm | 
| StorageInfo | Describes the disks mounted on the file system | 
| TimeZoneSelector | Allows users to configure their time zone information | 
| XmlHandler | XML document structure holder |