| CTK | Toolkit for biomedical image computing | Graphics, Widgets, Data | Apache-2.0 | |
| EasyQtSql | A lightweight header-only C++11 library for quick and easy SQL querying with QtSql | Data | MIT | |
| Enginio | Enginio client library for Qt platfom. Provides both Qt C++ and QML APIs to client applications. | Data, API, QML | GPLv3, LGPLv2.1 | |
| FF7tk | Toolkit for working with data from Final Fantasy 7 | Data | GPLv3+ | |
| KArchive | File compression | Data | LGPLv2.1+ | |
| KCoreAddons | Addons to QtCore | Text, Data | LGPLv2.1+ | |
| KDE PIM Libraries | KDE PIM Libraries | Data, Communication | LGPLv2.1+ | |
| KFileMetaData | A file metadata and text extraction library | Data | LGPLv2.1+ | |
| KHolidays | Holiday calculation library | Data | LGPLv2.1+ | |
| KImageFormats | Image format plugins for Qt | Graphics, Data | LGPLv2.1+ | |
| KIO | Resource and network access abstraction | Communication, Data | LGPLv2.1+ | |
| KLFBackend | KLatexFormula backend library | Graphics, Data | GPLv2+ | |
| KNewStuff | Support for downloading application assets from the network | Data, Communication | LGPLv2.1+ | |
| Kode | Code generation library | Development, Data | LGPLv2.1+ | |
| KPeople | Provides access to all contacts and the people who hold them | Communication, Data | LGPLv2.1+ | |
| KUnitConversion | Support for unit conversion | Data | LGPLv2.1+ | |
| TmdbQt | Library for querying The Movie Database API (themoviedb.org) | API, Data | LGPLv2.1+ | |
| NCReport | Report generator | Printing, Data | Commercial | |
| Nut | Object relational mapper for Qt5 | Data | GPLv3, LGPLv3 | |
| QDataCube | Datacube for Qt | Data, Widgets | LGPL | |
| qdbf | Library for handling dbf files | Data | LGPLv2.1+ | |
| QDecimail | Decimal arithmetic library for Qt framework | Data | LGPL v2.1 | |
| QicsTable | High performance Qt table widget | Widgets, Data | GPLV3+, LGPLv2.1+, Commercial, Evaluation | |
| QJson | JSON parser for Qt | Data | LGPL | |
| QJsonRpc | Implementation of the JSON-RPC protocol | Data, Communication | LGPLv2.1+ | |
| QSqlMigrator | QSqlMigrator - keep track of your database migrations | Data | LGPLv2.1, GPLv3 | |
| QtFirebase | An effort to bring the Firebase C++ API to Qt + QML | QML, Mobile, API, Data | MIT | |
| qtoolbox | Set of tools for Qt development | Data, Logging | Apache-2.0 | |
| QtORM | Object relational model inspired from Django | Web, Data | LGPLv2.1 | |
| QtPromise | Promises/A+ implementation for Qt/C++ | Data, Development | MIT | |
| QtUnits | Qt runtime unit conversion library built using (and compatible with) Boost::Units. | Data | BSD 2-clause | |
| Qt Xlsx | .xlsx file reader and writer for Qt5 | Data | MIT | |
| QuaZIP | Qt/C++ wrapper for ZIP/UNZIP package | Data | LGPLv3+ | |
| QxOrm | Qt-based Object Relational Mapping (ORM) | Data | GPLv3, Commercial | |
| Soprano | Qt/C++ RDF framework | Data | LGPLv2.1+ | |
| SQLate | type-safe template-based SQL support using Qt | Data | LGPL |