The MP for Hampstead and Kilburn previously held the position in 2017 before quitting over the Article 50 vote.
Siddiq replaces Tracy Brabin, MP for Batley and Spen, who was named shadow culture secretary earlier this month.
Brabin said she was “delighted” for Siddiq adding: “She’s a class act and early years has a true champion!”
Shadow education secretary Angela Rayner announced the appointment on Twitter, saying: “Absolutely delighted to announce that Tulip Siddiq has been appointed shadow early years minister and will be joining our shadow education team.
“I have worked with Tulip before and she will be a tremendous addition to our shadow front bench team scrutinising the government.”
Absolutely delighted to announce that @TulipSiddiq has been appointed shadow early years minister and will be joining our shadow education team. I have worked with Tulip before and she will be a tremendous addition to our shadow front bench team scrutinising the government 👍 pic.twitter.com/LvI0JzrQYi— Angela Rayner 🌈 (@AngelaRayner) January 14, 2020
Siddiq served as chair of the All-Party Parliamentary Group (APPG) for Childcare and Early Education from its launch in September 2017 until December 2019.
She said of her appointment: "I’m delighted to be appointed the shadow minister for early years as part of Angela Rayner’s shadow education team. Early years education is a crucial part of a child’s development, with many from disadvantaged backgrounds falling behind before they even start school. I hope to work with my Labour colleagues to make sure this doesn’t happen.
"There has never been a more vital time to be holding the government to account on its continued underfunding and undervaluing of early years providers. I want to hit the ground running, and with the Budget coming up, I will be putting pressure on the Chancellor to give the sector much needed help, whether that be with more core funding, changes to VAT or a reduction in business rates."
Purnima Tanuku, chief executive of National Day Nurseries Association (NDNA), said: "We would like to congratulate Tulip Siddiq on her appointment the shadow early years brief. We have worked closely with Tulip as chair of the All-Party Parliamentary Group for Childcare and Early Education where she has challenged the government on the funding crisis in early years.
"She is well aware of the challenges that nurseries and other childcare providers are currently facing and so we are confident she will raise these at the highest level in Parliament. The Government must be held to account at this critical time for early years when it is increasing minimum wages but not boosting funding rates to keep pace with these rising costs."
Neil Leitch, chief executive of the Early Years Alliance, added: "We’re very pleased to see Tulip Siddiq return to the role of shadow early years minister. During her time as chair of the APPG for Childcare and Early Education she was a passionate and dedicated advocate for funding levels that cover the true cost of delivering quality childcare who understood the challenges the sector faces.
"The coming months are an especially vital time for the sector with the end of the funding freeze, the budget and a probably spending review giving the government ample opportunity to reset the debate when it comes to the sector’s ongoing sustainability. We look forward to working with Tulip to ensure these chances are not wasted."