Innovative STEM Networks Act or the I-STEM Act - Amends the Elementary and Secondary Education Act of 1965 to direct the Secretary of Education to award competitive grants to states or local educational agencies (LEAs) to establish STEM (science, technology, engineering, or mathematics) innovation networks in partnership with nonprofit organizations, businesses, institutions of higher education (IHEs), educational service agencies, or other entities to prepare students for postsecondary education and careers in the STEM fields.

Directs the Secretary of Education to: (1) award no less than 5 and no more than 10 of those grants each fiscal year, and (2) give priority to grantees that include or serve a high-need LEA.

Requires the grants to be used to:

• increase student awareness about STEM career pathways that reflect STEM workforce needs in the area,
• develop statewide plans that integrate and align workforce needs with STEM education and training programs that provide students with STEM-specific skills and credentials, and
• identify the strengths and weaknesses in state STEM education efforts and prioritize strategies to address those weaknesses.

Authorizes the grants to be used to:

• promote and develop in-school and out-of-school curricular tools and professional development for STEM educators at the elementary and secondary school level;
• provide induction and mentoring services to new teachers in STEM subjects;
• promote and develop rigorous undergraduate pre-service teacher programs at IHEs that emphasize STEM content;
• support the participation of elementary and secondary school students in STEM-related competitions, out-of-school activities, and field experiences;
• assist in the implementation and assessment of rigorous career and college ready standards in STEM education for students in prekindergarten through grade 12; and
• develop STEM-related education and workforce training programs in secondary schools and community colleges that reflect local community needs.