Understanding implementation-related factors and processes is key to ensuring that Internet-based interventions are embedded in practice and provide added value to the delivery of evidence-based care. The aim of this study was to evaluate the attitudes towards an Internet-based cognitive behavioural therapy (iCBT) intervention for the treatment of depression as well as its level of normalization and early implementation success (operationalized as intention to use the intervention) among German health care professionals (HCP). Data were collected following onetime information sessions on an iCBT tool using the Evidence-Based Practice Attitude Scale (EBPAS) and the Normalization Process Theory Measure (NoMAD). Influences of attitudes on normalization as well as influences of attitude and normalization on intention to use were analysed. Most participants (n = 78; 86.3% clinical psychologists, 9.6% general practitioners) intended to use the intervention in the future (82.1%) and had a moderately positive attitude towards iCBT interventions. The perceived level of normalization (i.e., the level of how well iCBT is integrated in practice) was moderate in the overall sample. High appeal, openness towards iCBT, low requirement to use it, and low perceived divergence (perceived difference between current and new practices) had a significant positive effect on normalization. This study indicates that iCBT can be implemented in German routine mental healthcare. However, implementation processes might benefit from tailored information campaigns that clearly highlight the effectiveness and benefits of iCBT interventions to foster openness towards iCBT interventions among HCPs.