Introduction This retrospective open cohort study develops and externally validates a clinical prediction model (CPM) to predict the joint risk of two important outcomes occurring within the next year in people with epilepsy (PWE): A) seizure-related emergency department or hospital admission; and B) epilepsy-related death. This will provide clinicians with a tool to predict either or both of these common outcomes. This has not previously been done despite both being potentially avoidable, interrelated, and devastating for patients and their families. We hypothesise that the CPM will identify individuals at high or low risk of either or both outcomes. We will guide clinicians on proposed actions to take based on the overall risk score. Methods and analysis Routinely collected electronic health data from Clinical Practice Research Datalink (CPRD), Secure Anonymised Information Linkage databank (SAIL), Combined Intelligence for Population Health Action (CIPHA), and TriNetX research platforms will be used to identify PWE aged ≥16 years having outcomes A and/or B between 2010-2022. Data are held for 60 million patients in England on CPRD, 3.1m in Wales on SAIL, 2.6m in Cheshire and Merseyside on CIPHA, and 250m across 19 countries in TriNetX. Candidate predictors will include demographic, lifestyle, clinical, and management. Logistic regression and multistate modelling will be used to develop a suitable CPM (informed by clinician and public consultation), assessing predictive performance across development (CPRD) and external validation (SAIL, CIPHA, TriNetX) datasets. Conclusions This is the largest study to develop and validate a CPM for PWE, creating an internationally generalisable tool for subsequent clinical implementation. It is the first to predict the joint risk of acute admissions and death in PWE. Mortality prediction is highlighted by NICE as a key recommendation for epilepsy research. The study has been co-developed by epilepsy researchers and members of the public affected by epilepsy.