Introduction: Improving adherence to nicotine replacement therapy (NRT) in pregnancy may result in higher smoking cessation rates. Informed by the Necessities and Concerns Framework, we developed an intervention targeting pregnancy NRT adherence. To evaluate this, we derived the NRT in pregnancy necessities and concerns questionnaire (NiP-NCQ), which measures perceived need for NRT and concerns about potential consequences. Aims and Methods: Here we describe the development and content validation of NiP-NCQ. From qualitative work, we identified potentially modifiable determinants of pregnancy NRT adherence and classed these as necessity beliefs or concerns. We translated these into draft self-report items and piloted items on 39 pregnant women offered NRT and a prototype NRT adherence intervention, assessing distributions and sensitivity to change. After removing poorly performing items, smoking cessation experts (N = 16) completed an online discriminant content validation (DCV) task to determine whether retained items measure a necessity belief, concern, both, or neither construct. Results: Draft NRT concern items encompassed safety for the baby, side effects, too much or insufficient nicotine, and addictiveness. Draft necessity belief items included perceived need for NRT for short- and longer-term abstinence, and desire to minimize or cope without NRT. Of 22 out of 29 items retained after piloting, four were removed following the DCV task: three were judged to measure neither construct and one possibly both. The final NiP-NCQ comprised nine items per construct (18 total). Conclusions: The NiP-NCQ measures potentially modifiable determinants of pregnancy NRT adherence within two distinct constructs and may have research and clinical utility for evaluating interventions targeting these. Implications: Poor adherence to NRT in pregnancy may result from low perceived need and concerns about consequences; interventions challenging these beliefs may yield higher smoking cessation rates. To evaluate an NRT adherence intervention informed by the Necessities and Concerns Framework, we developed the NiP-NCQ. Through the content development and refinement processes described in this paper, we derived an evidence-based, 18-item questionnaire measuring two distinct constructs within two nine-item subscales. Higher concerns and lower necessity beliefs indicate more negative NRT beliefs; NiP-NCQ may have research and clinical utility for interventions targeting these.