STEM Innovation Networks Act of 2013 - Directs the Secretary of Education to award matching grants to state-based science, technology, engineering, and mathematics (STEM) networks or similar organizations of STEM stakeholders to expand STEM education and STEM educator development.

Includes among grant uses:

• testing, sharing, and scaling up STEM education research, promising practices, and exemplary programs;
• identifying state STEM education weaknesses and prioritizing strategies to address them;
• implementing rigorous career and college ready standards in STEM education;
• developing and implementing innovative STEM assessments that measure student progress toward those career and college ready standards;
• promoting and developing pre- and in-service STEM teacher training;
• developing STEM career pathways and workforce education and training programs that reflect 21st century workforce needs;
• facilitating the implementation of expanded STEM learning opportunities on school sites; and
• promoting, supporting, and designing programs that develop STEM content coaches and master educators in order to strengthen core competencies of the classroom practitioner.

Requires grantees to conduct periodic independent evaluations of their effectiveness in accomplishing those activities.

Prohibits the Secretary from: (1) endorsing or approving any STEM curriculum designed for use in an elementary school, secondary school, or institution of higher education; or (2) requiring a state, local educational agency, or school to adopt a specific STEM program or instructional materials.