The generation and control of spin polarization and valley polarization in antiferromagnets (AFMs) have garnered increasing attention due to their potential for enabling faster and more stable multifunctional spintronic and valleytronic memory and logic devices. However, the two primary categories of AFMs—altermagnets and $\mathcal{TP}$-symmetric AFMs ($\mathcal{T}$ is time reversal; $\mathcal{P}$ is spatial inversion)—either lack intrinsic valley polarization or net spin polarization. Here, we propose an effective approach for achieving spontaneous spin-valley polarization in $\mathcal{TP}$-broken layered ferroelectric antiferromagnets (FE-AFMs). The FE-AFMs exhibit lifted spin degeneracy across the entire Brillouin zone, along with uncompensated spin density of states. They combine the benefits of spin polarization in altermagnets with valley polarization in $\mathcal{TP}$-symmetric AFMs. Furthermore, the FE-AFMs feature layer-dependent spin polarization, rooted in their intrinsic ferroelectric property, allowing for the flexible control over spin-valley polarization by interlayer sliding. This tunability facilitates sign-reversible and size-tunable valley Hall and Nernst effects, along with other spin- and valley-dependent transport properties. Our findings are demonstrated in a broad class of $\mathcal{TP}$-broken bilayer antiferromagnets such as ${\mathrm{Nb}}_3{X}_8$ $(X=\mathrm{Cl}, \mathrm{Br}, \mathrm{I}),$ $\mathrm{V}{X}_2$ $(X=\mathrm{S}, \mathrm{Se})$, and ${\mathrm{VSi}}_2{X}_4$ $(X=\mathrm{N}, \mathrm{P})$, underscoring the potential of FE-AFMs for advancing next-generation spin- and valley-based information technologies.

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• Anomalous Hall effect
• Nernst effect
• Spin polarization
• Valley degrees of freedom
• Antiferromagnets
• Ferroelectrics
• Two-dimensional electron system