Why do I owe California state taxes this year, Im married filing jointly and I never owed taxes before.

[Mike9241]

all you can do is compare the 2022 and 2023 returns line for line. we can't see the return or the data used to prepare it so there can be numerous reasons.  here are just a few

1) more income

2) less taxes paid in

3) errors in entry

4) changes in tax laws

5)  Turbotax calculation error ( unlikely since there  have not been numerous threads that wer would see if this was the issue)

6) combination of abobe

[MonikaK1]

It depends. Owing state taxes can result from personal changes, job transitions, side jobs, and eligibility for tax credits and deductions.

It could also occur because you withheld too little for state taxes, or your earnings changed your entitlements to certain tax credits, such as the Earned Income Credit. 

You can owe state taxes while being up to date with your federal tax bill because the state tax brackets are different. See here for the California rate schedules.

You might check your W-2s or other information returns to see whether your State withholding was less than expected.

@bishoy-elmagaris