Is there a dress code in Jerusalem?

Yes. You will be allowed everywhere (I mean holy sites) and your life there will be easier. In a nutshell, be covered. And the same applies for men, it means no shorts for them and I find it very fair. I recommend no peeking underwear, no cleavage, no see-through clothes.

There isn't a dress code but visitors are expected to dress modestly at religious sites. Cover your shoulders, and legs above the knee, wear loose-fitting clothing and avoid mini-skirts, see-through clothing, and plunging necklines. You don't have to wear a hijab, but bring a scarf to cover your head when required! Men will be asked to cover their heads in synagogues with a kippah (yamaka).