Science, Technology, Engineering, and Mathematics (STEM) has received widespread attention worldwide and technology companies designed educational applications (apps) focusing on STEM. Young children have access to tablets and smartphones and they engage with a variety of apps every day. Prior research showed that young children learn from educational apps when they are used intentionally. However, children's caregivers may have limited information on finding educational apps and rely on the ratings on the digital app markets before downloading apps for their children. We evaluated the educational content and developmental appropriateness of 30 popular STEM applications in Turkey. The majority of the apps focused on science and math concepts, while engineering and technology concepts were often neglected. Most of the apps had higher scores on being bias-free and child-friendly but had lower scores on app features (sound quality, configuration ability, progress monitoring, and feedback) as well as providing social interaction opportunities. Most of the apps were available in English and the country's local language was often unavailable. App designers should design apps that encourage children's social interactions, include feedback and progress monitoring features for children and caregivers, and be available in the country's local language.