Zoom Meetings

CS50 occasionally holds live lectures (as well as office hours and even quiz shows!) via Zoom that anyone on the internet is welcome to attend, whether taking any of CS50’s courses or not!

For any Zoom meeting you attend, please take care to

  • participate from a quiet office or similar space (and not from a bed, car, hammock, plane, or train), and
  • participate with your camera turned on, using horizontal (not vertical) video.

If unable to accommodate these norms some week, please watch the live stream or recording at youtube.com/cs50, linkedin.com/school/CS50, or facebook.com/cs50 instead.


Fall 2021 of CS50 (which will become CS50x 2022 on edX on 1 January 2022) is in progress at Harvard and Yale, and CS50’s lectures are, as always, open to the public online!

Whether you are a CS50x student, a CS50 AP student, a prospective student, a teacher, a parent, or a Harvard alum (or anyone else!), you are cordially invited to attend one or more of Fall 2021’s lectures virtually. (It is not possible to attend physically in person this year.) All you need to attend is a computer or phone.

You’re welcome to attend one, some, or all of the lectures below. Upon registering, you’ll receive an email with a URL via which you can join the meeting with the time comes. Space is limited, so please forgive if the Zoom Meeting fills up! (Zoom allows up to 5,000 users to register for meetings but only allows 1,000 to attend.) But you’re welcome to watch live via YouTube instead!

Zoom Week Lecture Date YouTube
Register Week -1 Dress Rehearsal Watch
Register Week 0 Scratch Watch
Register Week 1 C Watch
Register Week 2 Arrays Watch
Register Week 3 Algorithms Watch
Register Week 4 Memory Watch
Register Week 5 Data Structures Watch
Register Week 6 Python Watch
Register Week 7 SQL Watch
Register Family Weekend Cybersecurity Watch
Register Week 8 HTML, CSS, JavaScript Watch
Register Week 9 Flask Watch
Register Week 10 Emojis Watch