diff --git a/apps/web/src/app/vision-training/train/components/TrainingDiagnosticsContext.tsx b/apps/web/src/app/vision-training/train/components/TrainingDiagnosticsContext.tsx
new file mode 100644
index 00000000..5ef25844
--- /dev/null
+++ b/apps/web/src/app/vision-training/train/components/TrainingDiagnosticsContext.tsx
@@ -0,0 +1,163 @@
+'use client'
+
+import { createContext, useContext, useMemo, type ReactNode } from 'react'
+import type {
+  SamplesData,
+  DatasetInfo,
+  EpochData,
+  TrainingConfig,
+  TrainingResult,
+} from './wizard/types'
+
+export interface DiagnosticReason {
+  type: 'imbalance' | 'insufficient-data' | 'poor-convergence' | 'unknown'
+  severity: 'warning' | 'error'
+  title: string
+  description: string
+  action: string
+  details?: {
+    underrepresented?: number[]
+    minCount?: number
+    maxCount?: number
+    totalImages?: number
+  }
+}
+
+interface TrainingDiagnostics {
+  // Raw data
+  samples: SamplesData | null
+  datasetInfo: DatasetInfo | null
+  epochHistory: EpochData[]
+  config: TrainingConfig
+  result: TrainingResult | null
+
+  // Computed diagnostics
+  shouldShowRemediation: boolean
+  reasons: DiagnosticReason[]
+}
+
+const TrainingDiagnosticsContext = createContext<TrainingDiagnostics | null>(null)
+
+export function useTrainingDiagnostics(): TrainingDiagnostics {
+  const ctx = useContext(TrainingDiagnosticsContext)
+  if (!ctx) {
+    throw new Error('useTrainingDiagnostics must be used within TrainingDiagnosticsProvider')
+  }
+  return ctx
+}
+
+interface ProviderProps {
+  samples: SamplesData | null
+  datasetInfo: DatasetInfo | null
+  epochHistory: EpochData[]
+  config: TrainingConfig
+  result: TrainingResult | null
+  children: ReactNode
+}
+
+export function TrainingDiagnosticsProvider({
+  samples,
+  datasetInfo,
+  epochHistory,
+  config,
+  result,
+  children,
+}: ProviderProps) {
+  const diagnostics = useMemo(() => {
+    const reasons = analyzeDiagnostics(result, samples, datasetInfo, epochHistory)
+    const accuracy = result?.final_accuracy ?? 0
+
+    return {
+      samples,
+      datasetInfo,
+      epochHistory,
+      config,
+      result,
+      shouldShowRemediation: accuracy < 0.5 || (accuracy < 0.7 && reasons.length > 0),
+      reasons,
+    }
+  }, [samples, datasetInfo, epochHistory, config, result])
+
+  return (
+    <TrainingDiagnosticsContext.Provider value={diagnostics}>
+      {children}
+    </TrainingDiagnosticsContext.Provider>
+  )
+}
+
+function analyzeDiagnostics(
+  result: TrainingResult | null,
+  samples: SamplesData | null,
+  datasetInfo: DatasetInfo | null,
+  epochHistory: EpochData[]
+): DiagnosticReason[] {
+  if (!result) return []
+
+  const accuracy = result.final_accuracy
+  const reasons: DiagnosticReason[] = []
+
+  // 1. Check for data imbalance
+  if (samples) {
+    const counts = Object.values(samples.digits).map((d) => d.count)
+    const max = Math.max(...counts)
+    const min = Math.min(...counts)
+
+    if (max > min * 5 && min < 10) {
+      const underrepresented = Object.entries(samples.digits)
+        .filter(([, d]) => d.count < max / 3)
+        .map(([digit]) => parseInt(digit, 10))
+
+      reasons.push({
+        type: 'imbalance',
+        severity: 'error',
+        title: 'Data imbalance',
+        description: `Some digits have very few samples (${min}) while others have many (${max})`,
+        action: `Collect more samples for digits: ${underrepresented.join(', ')}`,
+        details: { underrepresented, minCount: min, maxCount: max },
+      })
+    }
+  }
+
+  // 2. Check for insufficient total data
+  const total = datasetInfo?.total_images ?? samples?.totalImages ?? 0
+  if (total < 200) {
+    reasons.push({
+      type: 'insufficient-data',
+      severity: total < 100 ? 'error' : 'warning',
+      title: 'Insufficient training data',
+      description: `Only ${total} images available`,
+      action: 'Collect at least 200 images (20+ per digit)',
+      details: { totalImages: total },
+    })
+  }
+
+  // 3. Check for poor convergence (accuracy barely improved during training)
+  if (epochHistory.length >= 2) {
+    const firstAcc = epochHistory[0]?.val_accuracy ?? 0
+    const lastAcc = epochHistory[epochHistory.length - 1]?.val_accuracy ?? 0
+    const improvement = lastAcc - firstAcc
+
+    if (improvement < 0.1 && accuracy < 0.5) {
+      reasons.push({
+        type: 'poor-convergence',
+        severity: 'warning',
+        title: 'Model failed to learn',
+        description: 'Accuracy barely improved during training',
+        action: 'Check data quality - images may be too noisy or inconsistent',
+      })
+    }
+  }
+
+  // 4. Unknown issue if accuracy is bad but no clear reason
+  if (accuracy < 0.5 && reasons.length === 0) {
+    reasons.push({
+      type: 'unknown',
+      severity: 'warning',
+      title: 'Unexpected low accuracy',
+      description: 'Data appears adequate but accuracy is poor',
+      action: 'Try training again or review captured images for quality issues',
+    })
+  }
+
+  return reasons
+}
diff --git a/apps/web/src/app/vision-training/train/components/wizard/ExpandedCard.tsx b/apps/web/src/app/vision-training/train/components/wizard/ExpandedCard.tsx
index 9ef3fa1a..f678c1c3 100644
--- a/apps/web/src/app/vision-training/train/components/wizard/ExpandedCard.tsx
+++ b/apps/web/src/app/vision-training/train/components/wizard/ExpandedCard.tsx
@@ -141,7 +141,14 @@ export function ExpandedCard({
       case 'export':
         return <ExportCard message={statusMessage} />
       case 'results':
-        return <ResultsCard result={result} error={error} onTrainAgain={onTrainAgain} />
+        return (
+          <ResultsCard
+            result={result}
+            error={error}
+            configuredEpochs={config.epochs}
+            onTrainAgain={onTrainAgain}
+          />
+        )
       default:
         return null
     }
diff --git a/apps/web/src/app/vision-training/train/components/wizard/cards/ResultsCard.tsx b/apps/web/src/app/vision-training/train/components/wizard/cards/ResultsCard.tsx
index 48c84c9a..6fe60533 100644
--- a/apps/web/src/app/vision-training/train/components/wizard/cards/ResultsCard.tsx
+++ b/apps/web/src/app/vision-training/train/components/wizard/cards/ResultsCard.tsx
@@ -3,16 +3,19 @@
 import { useState } from 'react'
 import { css } from '../../../../../../../styled-system/css'
 import { ModelTester } from '../../ModelTester'
+import { useTrainingDiagnostics, type DiagnosticReason } from '../../TrainingDiagnosticsContext'
 import type { TrainingResult } from '../types'
 
 interface ResultsCardProps {
   result: TrainingResult | null
   error: string | null
+  configuredEpochs: number
   onTrainAgain: () => void
 }
 
-export function ResultsCard({ result, error, onTrainAgain }: ResultsCardProps) {
+export function ResultsCard({ result, error, configuredEpochs, onTrainAgain }: ResultsCardProps) {
   const [activeTab, setActiveTab] = useState<'results' | 'test'>('results')
+  const diagnostics = useTrainingDiagnostics()
 
   if (error) {
     return (
@@ -169,7 +172,15 @@ export function ResultsCard({ result, error, onTrainAgain }: ResultsCardProps) {
               <div className={css({ color: 'gray.600', fontSize: 'xs' })}>Epochs</div>
               <div className={css({ fontFamily: 'mono', color: 'gray.300', fontWeight: 'medium' })}>
                 {result.epochs_trained ?? '—'}
+                {result.epochs_trained && result.epochs_trained < configuredEpochs && (
+                  <span className={css({ color: 'gray.500' })}>/{configuredEpochs}</span>
+                )}
               </div>
+              {result.epochs_trained && result.epochs_trained < configuredEpochs && (
+                <div className={css({ color: 'green.500', fontSize: 'xs', fontWeight: 'medium' })}>
+                  converged
+                </div>
+              )}
             </div>
             <div>
               <div className={css({ color: 'gray.600', fontSize: 'xs' })}>Final Loss</div>
@@ -192,6 +203,11 @@ export function ResultsCard({ result, error, onTrainAgain }: ResultsCardProps) {
             </div>
           )}
 
+          {/* Remediation advice for poor results */}
+          {diagnostics.shouldShowRemediation && (
+            <RemediationSection reasons={diagnostics.reasons} />
+          )}
+
           {/* Train again button */}
           <button
             type="button"
@@ -218,3 +234,48 @@ export function ResultsCard({ result, error, onTrainAgain }: ResultsCardProps) {
     </div>
   )
 }
+
+/** Shows diagnostic reasons and remediation advice for poor training results */
+function RemediationSection({ reasons }: { reasons: DiagnosticReason[] }) {
+  if (reasons.length === 0) return null
+
+  return (
+    <div
+      data-element="remediation-section"
+      className={css({
+        mt: 4,
+        mb: 4,
+        p: 3,
+        bg: 'yellow.900/30',
+        border: '1px solid',
+        borderColor: 'yellow.700',
+        borderRadius: 'lg',
+        textAlign: 'left',
+      })}
+    >
+      <div
+        className={css({
+          display: 'flex',
+          alignItems: 'center',
+          gap: 2,
+          mb: 2,
+          fontWeight: 'semibold',
+          color: 'yellow.400',
+          fontSize: 'sm',
+        })}
+      >
+        <span>⚠️</span>
+        <span>Why is accuracy low?</span>
+      </div>
+
+      <div className={css({ display: 'flex', flexDirection: 'column', gap: 2 })}>
+        {reasons.map((reason, i) => (
+          <div key={i} className={css({ fontSize: 'xs' })}>
+            <div className={css({ color: 'gray.200', fontWeight: 'medium' })}>• {reason.title}</div>
+            <div className={css({ color: 'gray.400', ml: 3 })}>{reason.action}</div>
+          </div>
+        ))}
+      </div>
+    </div>
+  )
+}
diff --git a/apps/web/src/app/vision-training/train/page.tsx b/apps/web/src/app/vision-training/train/page.tsx
index 301400d1..b0c21944 100644
--- a/apps/web/src/app/vision-training/train/page.tsx
+++ b/apps/web/src/app/vision-training/train/page.tsx
@@ -3,6 +3,7 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import Link from 'next/link'
 import { css } from '../../../../styled-system/css'
+import { TrainingDiagnosticsProvider } from './components/TrainingDiagnosticsContext'
 import { TrainingWizard } from './components/wizard/TrainingWizard'
 import type {
   SamplesData,
@@ -446,29 +447,37 @@ export default function TrainModelPage() {
         </div>
 
         {/* Training Wizard - handles all phases */}
-        <TrainingWizard
+        <TrainingDiagnosticsProvider
           samples={samples}
-          samplesLoading={samplesLoading}
-          hardwareInfo={hardwareInfo}
-          hardwareLoading={hardwareLoading}
-          fetchHardware={fetchHardware}
-          preflightInfo={preflightInfo}
-          preflightLoading={preflightLoading}
-          fetchPreflight={fetchPreflight}
-          config={config}
-          setConfig={setConfig}
-          serverPhase={serverPhase}
-          statusMessage={statusMessage}
-          currentEpoch={currentEpoch}
-          epochHistory={epochHistory}
           datasetInfo={datasetInfo}
+          epochHistory={epochHistory}
+          config={config}
           result={result}
-          error={error}
-          onStart={startTraining}
-          onCancel={cancelTraining}
-          onReset={resetToIdle}
-          onSyncComplete={fetchSamples}
-        />
+        >
+          <TrainingWizard
+            samples={samples}
+            samplesLoading={samplesLoading}
+            hardwareInfo={hardwareInfo}
+            hardwareLoading={hardwareLoading}
+            fetchHardware={fetchHardware}
+            preflightInfo={preflightInfo}
+            preflightLoading={preflightLoading}
+            fetchPreflight={fetchPreflight}
+            config={config}
+            setConfig={setConfig}
+            serverPhase={serverPhase}
+            statusMessage={statusMessage}
+            currentEpoch={currentEpoch}
+            epochHistory={epochHistory}
+            datasetInfo={datasetInfo}
+            result={result}
+            error={error}
+            onStart={startTraining}
+            onCancel={cancelTraining}
+            onReset={resetToIdle}
+            onSyncComplete={fetchSamples}
+          />
+        </TrainingDiagnosticsProvider>
       </main>
     </div>
   )