CPT invariance is a key pillar in our description of nature. Neutrinos, as elementary particles, provide a unique opportunity to test this fundamental symmetry. CPT violation could manifest as particles and antiparticles having different masses. From a separate analysis of neutrino and antineutrino data, one can set bounds on CPT violation in the neutrino sector. We show how next-generation solar neutrino and medium-baseline reactor experiments will allow constraining, or proving, CPT violation with unprecedented sensitivity.