The  ordinance on admission to studies at the University of Zurich (currently only available in German) sets down the general terms of admission to studies at the University of Zurich. It applies to anyone applying for admission to studies at the University, regardless of the level.

The framework ordinance governing study in the Faculty of Science's Bachelor's and Master's degree programs sets down the general terms of Bachelor's and Master's degree programs at the Faculty of Science. The program regulations governing study in the Faculty of Science's Bachelor's and Master's degree programs contains detailed information on all the major and minor programs (modules, exams, and credits) on offer. The framework ordinance takes precedence over the program regulations. Each subject also publishes information in guidelines that you can find on the homepage of the subject in question.  The framework ordinance and the program regulations are legally binding.

Framework ordinance governing study in the Bachelor's and Master's degree programs offered by the University of Zurich's Faculty of Science (currently only available in German)

Framework ordinance governing study in the Bachelor's and Master's degree programs offered by University of Zurich's Faculty of Science - Start of studies in the Fall Semester 2021 or later (PDF, 86 KB) (currently only available in German)

Program regulations governing the Bachelor's and Master's study programs offered by the University of Zurich's Faculty of Science (PDF, 110 KB) (Part A, General Provisions)

Regulations for Students Commencing Studies from Fall Semester 2011

Ordinance for obtaining a doctoral degree from fall semester 2011 (currently only available in German)
Changes to the Ordinance from March 4, 2019 (PDF, 29 KB) (currently only available in German)
Ordinance for the joint doctoral degree MNF ETHZ (currently only available in German)
Ordinance for obtaining a doctoral degree from fall semester 2011 (Part A, General Section) (PDF, 211 KB)

Part B of the relevant doctoral program also applies in addition to the general ordinances.

Ordinances governing doctoral programs (Part B)

Framework ordinance governing study in the Joint Degree Master's Program Neural Systems and Computation (currently only available in German).
Program regulations (PDF, 229 KB) for the Joint Degree Master's Programm Neural Systems and Computation.

Framework ordinance governing study in the Joint Degree Master's Program Computational Biolog and Bioinformatics.
Program regulations (PDF, 155 KB) for the Joint Degree Master's Programm Computational Biology and Bioinformatics.