PyQChem is a Python module designed for an intuitive manipulation of Q-Chem input and output files. It was written with special focus on the features of IPython such as tab completion and easy access to help docstrings via the question mark operator. On the input side, the module supports batch jobfiles, simplified editing of molecular geometries, and comes with a large library of $rem keywords accessible via tab completion. Besides allowing to set up an entire inputfile within Python (which is very convenient in case of repeated tasks e.g. for building databases), the module can also schedule and execute Q-Chem files if the main program is installed on the same machine or accessible via a server. On the output side, pyQChem performs an automatic parsing of single or multi-job Q-Chem output files and stores the information it finds in conveniently structured objects. If frequencies are found in the output file, thermochemistry information can be calculated a posteriori for any temperature or pressure of interest. A correction for low-lying vibrational frequencies [Grimme, Chemistry - A European Journal 2012, 18, 9955-9964] can be automatically included if desired. The module further contains a large library of standard molecular test sets and a collection of typical physical constants and conversion factors as they are often needed in computational chemistry. Use conda to add the latest release of pqQChem to your environment (recommended), conda install -c awhauser pyqchem or clone and install the current Github development version via git clone https://github.com/hauser-group/pyQChem.git cd pyQChem pip install . Two IPython notebooks (and support files) are provided as an introduction to basic inputfile handling and outputfile parsing. Example Python scripts that use pyQChem can be found in the 'demos' directory. Note that the Q-Chem computational chemistry package itself is proprietary software and obviously not part of this python module. For more details, please have a look at the Q-Chem homepage. Andreas W. Hauser, Matthew Goldey, Ehud Tsivion, Ralf Meyer and Thomas Heavey